Ice it: apply an ice cube for about 5 minutes directly to the cold sore. Then let it warm up. Repeat a few times. It really works! It seems to mess the virus up and allow your body to heal normally within a day or so. If not, the virus will keep noodling 'round, keeping the cold sore open and weeping virus for a few days at least. Yukko! Lysine: meh... they say taking the amino acid supplement l-Lysine messes the virus up somehow. Can't hurt.