Hi,
What kind of substrate are you using at the moment? With injuries on the underside of the snake especially it might be agood idea to use paper towel or newspaper to help keep it clean if you are not using those already.
So do you think it was caused by getting caught or something against cage furniture? What kind of antibiotic ointment did you use? - the one I see recommended on here most of the time is neosporin (making sure it is the kind without pain killers).
It should heal up after a shed ( or two) I would think if it's that minor but remember to keep an eye on it for signs of infecion and if you are in any way worried about it a vet visit might be an option worth considering. A vet may even want to prescribe some anti-bios as a precaution if you take him in.
dr del