Fever blisters are small sore spots that sometimes appear on or near someone's lips and nose when they have a cold. (AM; in BRIT, usually use cold sore )
N-COUNT
blister
SMALL POCKET OF FLUID WITHIN THE UPPER LAYERS OF THE SKIN
A blister is a painful swelling on the surface of your skin. Blisters contain a clear liquid and are usually caused by heat or by something repeatedly rubbing your skin.
N-COUNT
2.
When your skin blisters or when something blisters it, blisters appear on it.
The affected skin turns red and may blister...
The sap of this plant blisters the skin.
...pausing to bathe their blistered feet.
VERB: V, Vn, V-ed
blister
SMALL POCKET OF FLUID WITHIN THE UPPER LAYERS OF THE SKIN