Holden has THE worst diaper rash ever

He's taking augmentin for a staph infection and the stupid stuff is causing horrible diarrhea and an even worse diaper rash. I can't even use a wipe to clean him up. I have to take him to the sink cause the wipes hurt him. I'm tempted to stop giving him the medicine (the infection has almost completely cleared up) but I want to get his Dr's opinion before I do that, and of course...they're closed for the day.
I've been using extra strength desitin and the I have beadreaux's butt paste for the babysitter to use, but neither seem to be working. Ughh its sop frustrating to see it and know its hurting him.