well herpes isn't curable so once u get the virus it stays in your system for the rest of you life. It is contagious but only when u are having an "outbreak" which is the "bump" or sore that your seeing on your lip
Go to the health food store and buy some L-Lysine. It's an essential amino acid. It prevents or treats herpes outbreaks. 1,500 mgs. will take care of it. And if you take 500-1000 mg daily, it will keep them from coming back. Also B vitamins and Vitamin C are helpful.
You are either still having an outbreak or you have a bump from irritating or biting your lip. If it looks like the outbreak you had, then you're still having an outbreak and need to be extra careful not to share eating utensils/food with anyone or kiss or go down on anyone so you don't give it to anyone else. Also be careful to wash your hands after touching the sore at all. Make sure to get plenty of rest and generally take care of your body, because herpes only flares up when your immune system is weakened (hence the term cold sores).
If you keep having outbreaks, talk to your doctor about getting an antiviral like valtrex to help prevent outbreaks. Blistex medicated lip balm can help relieve the discomfort of the sore. There does seem to be some evidence for L-Lysine helping as well. Be sure to talk to a pharmacist if you take anything else, though, to make sure there won't be any interactions (this goes for most drug combos, especially if there's a prescription drug involved).