This could be a cold sore or a pimple. Cold sores are caused by the herpes simplex virus, and they're contagious. Signs and symptoms of cold sores include:
-Small, painful, fluid-filled blisters on a raised, red, painful area of your skin
-Pain or tingling, called the prodrome, often precedes the blisters by one to two days
-Usual duration of seven to 10 days
Cold sores usually appear on your lips. Occasionally, they occur on your nostrils, chin or fingers.