Usually they appear on or around the mouth area or privates. The blisters break, leaving ulcers or tender sores that will take up to a month to cure. To truly zap those sores, take 2500 mg of lysine ( an amino acid ) till the cold sore disappears.
Manifestly , while you treat the cold sore, use lip protection from wind and sun - Chapstick is good ( unflavored ). Here's a fab article about genital herpes treatment. And remember - no kissing while the sore is present.