Okay. You need to stop trying to feed him. If it's sick and has to have creams and crap rubbed on it, chances are it's stressed out and not in the mood to eat. Putting a pinky in the tank is not gonna make your snake decide to eat. You need to wait till the antibiotic treatment is finished then move him/her into a plastic tub, and do as I suggested. I'm giving you advice that should be used.
DO IT