Cold sores
Cold sores are small blisters that appear on or around the lips, caused by the herpes simplex virus. Once you have the virus, it stays in your body and can flare up from time to time. Most cold sores heal by themselves within about 7 to 10 days.
- Usually heals
- In 7 to 10 days
- Contagious
- From the first tingle until fully healed
- Best treatment
- Started at the first tingle
Common symptoms
- Tingling, itching or burning on the lip or around the mouth, often 1 to 2 days before anything appears
- Small fluid-filled blisters, which burst and weep
- The sore then dries and forms a crust, which falls off as it heals
- Sometimes a temperature, sore throat or swollen glands the first time you get one
What triggers a flare-up
Common triggers include another illness such as a cold or flu, tiredness, stress, strong sunlight, periods, or a minor injury to the lip. Many people can identify their own triggers.
What you can do yourself
- Antiviral cold sore creams are available from the pharmacy. They work best if you start them at the first tingle, before the blister appears, and they can slightly shorten the flare-up.
- Special cold sore patches can protect the sore and help it heal.
- Paracetamol or ibuprofen can ease soreness if they are suitable for you.
- Use a lip balm with sun protection if sunlight is a trigger.
- Try not to pick the sore, and wash your hands after touching it.
Avoiding spreading it
- Avoid kissing, and do not share lip balm, cups, cutlery, towels or razors while you have a sore.
- Avoid touching your eyes, and never put cold sore cream on your eyes.
- Avoid oral contact with anyone who has eczema, a weakened immune system, or with newborn babies. The virus can cause serious illness in these groups.
How PRX Pharmacy can help
Our pharmacists can recommend a suitable cream or patch and check it is right for you or your child. Talk to us at the first sign of a tingle.
When to get medical help
Contact your GP practice or call 111 the same day if:
- • A cold sore is near or in your eye, or your eye is painful, red or sensitive to light
- • You have eczema and a cold sore, and painful blisters or sores are spreading quickly over the skin
- • You have a weakened immune system (for example from chemotherapy, HIV or steroid medicine)
- • A baby under 4 weeks old has a blister, sore or rash
- • The cold sore has not started to heal after about 10 days, or is unusually large or painful
- • You get cold sores very often, or they are severe
- • You feel very unwell, or have a high temperature
If you are ever worried and unsure, ask us or call 111. Trust your instincts — it is always better to ask.
This guide is general information written by the PRX Pharmacy team. It does not replace advice from a pharmacist or doctor who knows your medical history.
Last updated 24 September 2026. Clinically reviewed by Milan Patel, Pharmacist on 24 September 2026.
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