Cold sore symptoms include:
- Small, painful, fluid-filled blisters on a raised, red area of your skin, typically around the mouth
- Pain or tingling, called the prodrome, often precedes the blisters by one to two days
- Usual duration of seven to 10 days
Cold sores most commonly appear on your lips. Occasionally, they occur on your nostrils, chin or fingers. And, although it's unusual, they may occur inside your mouth often on your gums or hard palate, which is the roof of your mouth. Sores appearing on other soft tissues inside your mouth, such as the inside of the cheek or the undersurface of the tongue, may be canker sores but aren't usually cold sores.
Signs and symptoms may not start for as long as 20 days after exposure to the herpes simplex virus, and usually last seven to 10 days. The blisters form, break and ooze. Then a yellow crust forms and finally sloughs off to uncover pinkish skin that heals without a scar.