A cold sore usually passes through five stages, beginning with tingling before the sore forms and ending with the sore healing completely. Most cold sores complete all five stages and go away on their own within about two weeks.
Stage 1: Tingling
Before the cold sore forms, many people begin to feel a tingling, itching, or burning sensation under the skin around their mouth. This usually occurs within about 24 hours of the development of a blister and is considered day one of the cold sore’s progression.
During first-time outbreaks, some people also experience some or all of the following symptoms:
- High fever
- Sore throat
- Swollen neck glands
- Sore throat
- Muscle aches
Stage 2: Blisters
On day two or three, the visible blisters appear. They are usually tiny, fluid-filled blisters and form in a cluster, usually near the edge of the mouth where the lip meets the skin.
Stage 3: Rupture
Around day four, the blisters rupture and begin to ooze fluid. The area will look like a shallow, red sore. This is the stage during which cold sores are the most contagious and painful.
Stage 4: Crusting
Over days five to eight, the open sores slowly begin to dry out, forming a yellowish or brownish crust. It’s important to allow the crust to crack or break on its own rather than picking at it.
Stage 5: Healing
Over days nine to 14, a series of scabs form over the area as the crust falls off. The scabs will decrease in size as the sore heals completely within the two-week period. If you do not pick at the scabs and allow them to flake off naturally, you shouldn’t experience any scarring.