What does a cold sore look like?

Herpes. Shallow, grey, sometimes with a slightly red border, quite tender.
Cold sores. Usually they look like blisters. Painful. Commonly on lips, mouth, nose and throat.

Related Questions

What does the start of a cold sore look like?

First. Most people describe a tingly sensation before any lesion appears. The cold sore starts out as a small blister usually.