A cold sore on the lip can be uncomfortable. It usually heals within a week or two. A cold sore looks like a blister. Other skin issues, like pimples and canker sores can also appear on the lips and may look similar to a cold sore.
In this article, we explore the symptoms, stages of healing, and treatments for a cold sore on the lip. We also look at other issues that can be easy to confuse with cold sores.
A cold sores looks like a blister. Within a few days, the blister usually breaks open and oozes fluid. It then crusts and forms a scab before healing and disappearing.
During a person’s first cold sore outbreak, they may experience:
- a burning sensation around the mouth
- a sore throat
- painful swallowing
- swollen glands
- a fever
- a headache
- aches and pains
Also, people may experience the following symptoms on or around the lip a few days before an outbreak:
- a burning sensation
- tingling or numbness
- a stinging or throbbing sensation
Sometimes people experience these symptoms but find that no sore appears.
Over-the-counter topical treatments can help cold sores heal and reduce the symptoms. These treatments may be:
- antiviral ointments, such as docosanol
- anesthetic ointments, such as benzocaine (Orajel), lidocaine, or tetracaine (Pontocaine)
It may also help to:
- apply a cool compress or ice pack to the sore or the general area when tingling sensations first occur
- use over-the-counter pain relief medication, such as ibuprofen or acetaminophen, to ease discomfort
- avoid foods that could cause a burning sensation, such as acidic fruits and spicy or salty food
If people have more severe cold sore outbreaks, they may need a prescription-strength medication, such as acyclovir (Zovirax) or penciclovir (Denavir).
Anyone with recurrent, frequent outbreaks may need to take antiviral medication daily to prevent outbreaks.
Cold sores result from an infection with the herpes simplex virus, most commonly herpes simplex virus type 1 (HSV1).
HSV1 is common, and people can easily transmit it to others. Most people develop the infection during childhood.
People with HSV1 can pass on the virus by:
- sharing foods, drinks, and utensils
- sharing lip balms, razors, and similar products and items
- skin-to-skin contact
The virus can lie dormant, and some people with it never show symptoms.
For others, certain factors can activate the virus and trigger an outbreak of cold sores. Triggers can include:
- sun exposure or sunburn
- cold wind
- a cold, the flu, or other illness
- hormonal changes
- physical exhaustion
- having a weakened immune system
A person may experience warning signs about 1–2 days before a cold sore forms. They may, for example, have a throbbing, tingling, or burning sensation on their lip.
About 48 hours after the initial symptoms, the sore breaks open. Fluid oozes from the sore before it crusts and forms a scab.
For most healthy people, cold sores heal and disappear without scarring in 5–15 days. If a cold sore lasts for more than 15 days, they might wish to see doctor to discuss treatment.
People may be able to prevent cold sore outbreaks by:
- wearing a lip balm with a sun protection factor, or SPF
- getting plenty of sleep and quality rest
- regular exercise to support the immune system and overall health
- know what may trigger an outbreak, and avoid or minimize where possible
- reduce stress or anxiety
Anyone who has frequent outbreaks may benefit from discussing treatments, such as antiviral medication, with a doctor.
Cold sores are contagious until they scab. Anyone with an active sore can help prevent the infection from spreading by avoiding:
- skin-to-skin contact, such as kissing, particularly with people who have weakened immune systems and children — especially newborns
- sharing any personal items, such as towels or toothbrushes
- sharing food, drinks, and utensils
- touching the sores, if possible
If touching a sore is unavoidable, it is important to wash the hands afterward.
Pimples can appear anywhere on the body, including the lip and the surrounding skin. They form when excess oil and dead skin cells block pores, and bacteria can also play a role.
Blisters may form on the lip due to:
- biting the lip
- contact with very hot food or drink
- infections, such as shingles
- contact dermatitis
- medications, such as nalidixic acid or furosemide (Lasix)
Blisters have a smooth, bubble-like appearance and contain clear fluid or blood.
Canker sores are round, raised, yellow or white bumps with a red outer rim.
They only form inside the mouth and may develop on the inner lips. They are not contagious.
Doctors are unsure what causes canker sores, but stress and nutritional deficiencies may play a part.
If it is unclear whether a bump on the lip is a cold sore, a doctor can help .
They may be able to identify the issue by sight after taking symptoms into consideration. A doctor can confirm the diagnosis by taking a sample of the tissue with a swab and sending it for testing.
A cold sore on the lip can cause discomfort, but it usually heals within a few days or weeks. Home care and over-the-counter medication may help speed recovery.
If a cold sore lasts longer than 15 days or if outbreaks are frequent or severe, it might be a good idea to see a doctor.