Cold Sores occur as small blisters around the lips and mouth, a small bumpy rash can also occur. Outbreaks are most commonly brought on by large amounts of stress. An outbreak is very irritating, and can also lead to intense itching. A cold sore or fever blister usually lasts several days. Once the blister bursts or ruptures, this signifies the end of the outbreak.
http://www.coldsoresfacts.com
