It'll heal on its own. He'll be fine. If it starts to turn BRIGHT red or shows other signs of infection, take him to the vet. Otherwise, leave it alone. Its a minor scrap.
It should heal okay, I think, but if you are concerned (or if it looks like it may be taking a bit longer to heal) you could try using Neosporin cream on it. If you do, make sure you get the normal type without any pain reliever, otherwise it's toxic to buns.