Rash on Tummy

I hope someone can help me.  My RikRak has a rash that this morning looks like a burn on his tummy.  He goes to physical therapy every week and his doctor has him on an antibiotic for it.  The doctor thinks it’s from not getting out of the spot quickly enough after he tinkles.  When he is home and not at therapy I wipe his tummy with diaper wipes after every trip to pee.  He also this week developed an abscess right above the elbow on his remaining front leg.  He is also on an antibiotic for that.  Last night it seemed to get huge so I sat with an ice pack on it.  Swelling went down and it eventually burst on its own and he certainly seems to feel better.  It is still draining today, so I’m keeping it clean and as dry as I can.  Any other advice anyone can give me?