Herpes simplex virus (HSV) can cause infections that affect the mouth, the face, the genitals, the skin, the buttocks, and the anal area.  This article will concentrate on non-genital herpes.  Many people acquire the virus and have no symptoms.  For others, painful blisters appear near the area where the virus entered the body.  Typically, the blisters heal completely but reappear at some point in the future when least expected (or desired).  In between attacks, the virus resides deep in the roots of the nerves that supply the involved area.  When herpes simplex lesions appear in their most common location, around the mouth and lips, people often refer to them as “cold sores” and “fever blisters.”