Lysine which can be found in pill form or in a topical form at any health food store and some grocery stores.
An ice cube pressed to the area for several minutes will decrease the blood flow to the area and reduce the chances of the sore spreading.
Tea tree oil will help it to dry out faster and also helps to disinfect it.
Hydrogen peroxide will help it to dry out and disinfect the area.
WARNING: DO NOT APPLY ANY OF THESE WITH YOUR HANDS.