I've had a few bites and they healed just fine. Just make sure you keep the tub clean and your snake should be fine. I really wouldn't worry too much unless there was a chunk missing. Keep a close eye on it. I think mine have all healed within a couple days.
Usually minor bites will heal up on their own. Leave him alone and let him digest for a day or two then take him out and have a look. If there's still an open wound at that point start dabbing on Neosporin (the kind without pain relief) once a day.