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Polynucleotide injections aftercare in the UK

Polynucleotide (PN) injections, sometimes described as PDRN-based skin boosters, are used in medical aesthetics to support skin quality. It is common to have some swelling and bruising afterwards, and this can feel more noticeable in delicate areas like the under-eyes.

If you are searching polynucleotide injections swelling how long UK, you are usually trying to work out what is normal, how quickly the puffiness should settle, and when symptoms might need urgent review. This guide sets out a realistic recovery timeline, practical aftercare, and the warning signs that should prompt you to contact your clinic.

What polynucleotides are (PN and PDRN) and why swelling happens

Polynucleotides are injectable materials derived from DNA fragments, used to stimulate skin repair processes. Treatment is delivered via small injections into the skin, and some protocols use a cannula depending on the area.

Swelling and bruising can happen for a few reasons:
– Needle or cannula trauma causes minor local inflammation.
– Fluid shifts occur because the body sends inflammatory cells and extra fluid to the area as part of healing.
– The under-eye region (tear trough and lower eyelid) has thin skin and tends to retain fluid, so even mild swelling can look significant.
– Individual factors like easy bruising, allergies, rosacea, hay fever, or recent alcohol intake can increase visible swelling.

Polynucleotide treatments are not the same as dermal filler. However, both involve injections and can cause similar short-term injection-related side effects.

Day-by-day recovery timeline (including under-eye notes)

Everyone heals differently, and the amount injected, injection depth, technique, and your own tendency to bruise all matter. The timeline below is a typical guide rather than a guarantee.

0 to 6 hours

You may notice:
– Mild stinging or tenderness
– Small raised bumps at injection points (like tiny wheals)
– Warmth or mild redness

Under-eye notes:
– Swelling can look dramatic early on because the lower eyelid holds onto fluid.
– You may look more puffy when you first get home, then improve overnight, or you may swell more the next morning.

6 to 48 hours (Day 1 to Day 2)

This is usually the peak window for swelling.

Typical changes:
– Puffiness and tightness
– Bruising that starts as pink or red, then darkens
– Mild asymmetry, often from uneven swelling

Under-eye notes:
– Puffiness can be worst on waking.
– Hay fever, sinus congestion, salty meals, and poor sleep can make under-eye swelling more noticeable.
– Some people also get mild watery eyes or sensitivity, usually from local irritation rather than the eye itself.

Days 3 to 7

This is the settling phase.

Typical changes:
– Swelling gradually reduces day by day
– Bruises may change colour from purple to green, then yellow
– Small lumps or firmness at injection points can be felt, often more than they can be seen

Under-eye notes:
– If the area still looks puffy, it should generally be improving by the end of the week.
– A small amount of morning puffiness can persist longer under the eyes, particularly if you are prone to fluid retention.

Weeks 2 to 4

This is the longer recovery and response phase.

What to expect:
– Most injection-related swelling and bruising should be fully resolved.
– Skin quality changes, if they occur, are usually assessed over weeks rather than days.
– If you are having a course of treatments, your clinician may time sessions a few weeks apart.

Under-eye notes:
– Persistent under-eye puffiness beyond 2 weeks is not typical and should be assessed, especially if it is one-sided or worsening.

What is normal vs what is not

It helps to separate expected, short-lived after-effects from symptoms that need review.

Usually normal

• Mild to moderate swelling for 1 to 3 days, sometimes up to 7 days under the eyes
• Bruising that fades over 5 to 14 days
• Small bumps at injection sites for 24 to 72 hours
• Tenderness when pressing the area for a few days
• Mild asymmetry that matches uneven swelling and improves steadily

Needs a clinic review (non-urgent but should be checked)

• Lumps that persist beyond 2 weeks, feel firm, or are visible in normal lighting
• Prolonged puffiness that is not improving by day 7, especially under the eyes
• Marked asymmetry lasting more than a week
• Increasing redness after day 3 rather than gradual settling
• Itching, rash, or hives, which could indicate a reaction

Contact the clinic urgently (same day) if you notice red-flag symptoms

After polynucleotide injections, serious complications are uncommon, but you should seek urgent advice if you experience:
– Severe or worsening pain, especially if it is out of proportion to visible swelling
– Blanching, dusky colouring, or a net-like pattern on the skin near the injection area
– Coldness of the skin, or rapidly spreading discolouration
– Pus, weeping, or significant heat and swelling suggesting infection
– Fever or feeling unwell with increasing redness
– Vision symptoms such as blurred vision, double vision, loss of vision, or severe eye pain
– Shortness of breath, facial swelling, or throat tightness, which could indicate a serious allergic reaction

If vision symptoms occur, treat this as an emergency.

Aftercare do’s and don’ts

Your clinic may provide specific advice based on the product used and the area treated. The guidance below is commonly recommended after injectable treatments.

Do

• Keep the area clean and avoid touching unnecessarily.
• Use a cool compress (wrapped, not directly on skin) for short periods in the first 24 hours if advised. Do not use ice directly.
• Sleep on your back and consider an extra pillow for the first 1 to 2 nights to reduce morning puffiness.
• Stay hydrated and keep salt intake moderate for a few days, especially if you swell easily.
• Use gentle skincare: bland moisturiser, a mild cleanser, and SPF.

Don’t (first 24 to 48 hours unless your clinician advises otherwise)

• Do not exercise intensely. Heavy cardio and lifting can worsen swelling and bruising.
• Do not drink alcohol, as it can increase flushing and bruising.
• Do not use heat exposure, including saunas, steam rooms, hot yoga, very hot baths, or sunbeds.
• Do not massage the area unless your clinician specifically instructs you to.
• Do not apply active skincare over the treated area, especially retinoids, exfoliating acids (AHA/BHA), benzoyl peroxide, and strong vitamin C.

Makeup and skincare timing (practical guide)

This can vary by injection depth and skin sensitivity. When in doubt, follow your clinic’s instructions.

• Makeup: often avoided for at least 12 to 24 hours to reduce infection risk from brushes and sponges. Under-eye concealer can also tug at delicate skin, which may worsen irritation.
• Actives: commonly paused for 3 to 7 days, especially under the eyes.
• SPF: usually fine from the next day if the skin is intact and not irritated.

Under-eye swelling: why it can last longer and what helps

The under-eye area is prone to puffiness because:
– Skin is thin and shows fluid accumulation readily
– Lymphatic drainage is slower compared with other areas
– Small bruises and inflammation are more visible

Practical steps that may help in the first week:
– Cool compresses in short intervals during the first day if comfortable
– Sleeping slightly elevated
– Avoiding alcohol, salty meals, and intense exercise for 48 hours
– Managing hay fever symptoms if relevant (check with a pharmacist or your GP)

Avoid trying to “push swelling out” with massage, as this can irritate the area and potentially worsen bruising.

How long does swelling usually last in the UK after PN injections?

Most patients find that visible swelling improves significantly within 48 hours, with ongoing settling over 3 to 7 days. Under-eye puffiness can sometimes linger closer to a week. Bruising may last up to 2 weeks, especially if it tracks downwards with gravity.

Quick timeline table

Time after treatment	Typical swelling	Typical bruising	Under-eye notes
0 to 6 hours	Mild to moderate, bumps possible	Usually minimal	Puffiness can look prominent early
6 to 48 hours	Often peaks	May start or darken	Common to look worse on waking
Days 3 to 7	Settling	Colour changes, fading	Should be improving steadily
Weeks 2 to 4	Resolved	Resolved	Ongoing puffiness is not typical

Reducing risk before treatment

A good consultation should include a medical history and a discussion of bruising risk.

Medications and supplements

Do not stop prescribed medicines unless your GP or prescriber advises it. However, tell your clinician if you take:
– Aspirin, clopidogrel, warfarin, apixaban, rivaroxaban, or other blood thinners
– Anti-inflammatory medicines (some people bruise more easily)
– Supplements associated with bruising in some individuals, such as fish oil, high-dose vitamin E, garlic, ginkgo, and turmeric

Your clinician can advise what is appropriate for you.

Cold sores history

If you have a history of cold sores and you are treating around the mouth area, tell your clinician in advance. Preventative antiviral medication may be considered for some patients.

Event planning

If you have a wedding, filming, or an important event, plan treatment with time to spare:
– Allow at least 2 weeks if you need bruising risk to be minimal
– Consider 3 to 4 weeks if the under-eye area tends to swell or you have had prolonged bruising in the past

When to worry, and what to do next

A useful rule is that normal swelling should peak early and then steadily improve. If you are getting worse after day 3, if one side is significantly more swollen, or if you have severe pain, increasing redness, heat, discharge, fever, skin colour change, or any vision symptoms, you should contact the clinic urgently.

If you are unsure whether your symptoms are normal, it is safer to ask and be reviewed.

Calm next steps

If you have concerns about swelling, bruising, or under-eye puffiness after polynucleotide injections, you can be assessed by experienced medical professionals at Renovatio Clinic.