Small, painful blisters on the lip often appear with tiredness, stress or after sun. Knowing how to care for them and avoid spreading them helps you feel better and protect others.
- A cold sore is a cluster of small blisters on the lip caused by a virus and often returns with tiredness or stress.
- It can spread through direct contact with the blisters, so avoid kissing, sharing items and squeezing the sore.
- Keeping the lip clean, resting and protecting it from the sun help it heal, and very painful or recurring sores should be seen by a doctor.
- For non urgent dental work the dentist may advise waiting until the sore heals, while acute toothache still needs a visit.
Many people have had small blisters in a cluster on the lip or around the mouth that itch, sting and then break open and crust over. This is usually a cold sore, also called herpes labialis, caused by a virus. The virus can stay quiet in the body and flare up when resistance is low.
Signs to recognise
- A tingling or burning feeling on the lip before the blisters appear.
- Small blisters in a cluster on the lip or around the mouth.
- The blisters break, crust over and usually heal in about one to two weeks.
Is it contagious?
Yes. The virus spreads by direct contact with the blisters or their fluid, especially when they are weeping. So while you have a sore, you should:
- Avoid kissing and close contact with others, especially small children.
- Not share cups, utensils, towels or lipstick.
- Wash your hands after touching the sore, and never squeeze it or pick at the crust.
How should you care for it?
- Keep the lip clean and slightly dry, and avoid licking it.
- Apply a gentle cool compress to ease the burning.
- Rest, sleep enough and reduce stress, since tiredness makes recurrences more likely.
- Protect your lips from the sun, which can trigger a flare up.
- If it is very painful or keeps coming back, ask a doctor about suitable treatment and do not use medicine on your own.
Why tell the dentist before dental work?
While you have a blister on the lip, opening wide and working around the mouth easily makes it sore, cracked and spread further, and there is a risk of passing it on. For non urgent procedures such as scaling or a routine check, the dentist may advise waiting until the sore is dry and healed. For acute toothache you should still come, and tell us beforehand. See also how long mouth ulcers take to heal, since an ulcer inside the mouth is a different matter from a blister on the lip.
When should you see a doctor?
See a doctor if the sores spread, last longer than two weeks, are near the eyes, come with high fever, or you have a condition that lowers your resistance. Nha Khoa Ky Hoa is at 266A - 268, 3 Thang 2 Street, Hoa Hung Ward, Ho Chi Minh City. You can call the hotline 028.3868.1097 to ask first, or walk in during opening hours.
Frequently asked questions
Does a cold sore go away by itself?
It usually heals within about one to two weeks. If it spreads, lasts long or keeps returning, ask a doctor about treatment.
Should I squeeze a cold sore?
No. Squeezing or picking the crust easily spreads it, causes infection and can leave a scar.
Should I still have my teeth scaled while I have a cold sore?
For non urgent procedures, wait until the sore is dry and healed. If you have acute toothache, still come and tell the dentist beforehand.