If it is still infected: Cleanse it with something very gentle - eg. Dove soap, Pears, Cetaphil then use a benzoyl peroxide product twice a day on it. Get 2.5% if you can or failing that 5% - don't get PanOxyl - it's too severe. Get Oxy or Quinoderm. Put it on and let it dry. Then put a little moisturiser on top. That stops your surrounding skin drying too much. It bleaches anything that comes in contact so make sure you don't get it on your clothes. Be extremely gentle when doing this. Then DO NOT touch it at all until the next treatment time.
If it is not infected anymore the best thing is Emu oil - available on ebay. But you probably need something more readily available - so I suggest Sudacrem - get it in the supermarket - baby aisle. Don't be put off that it is for nappy rash - it works great at healing, believe me.