Bad diaper rash

What to do with a really bad diaper rash? He's 1, never had one this bad. I cant tell if it's a chemical burn from the diaper or a rash but its causing him pain, it hurts so bad he's shaking every time I try to wipe him and I cant not wipe him when he poops. I feel so bad. My SO said triple antibiotic? I wasnt sure if we could do that. I need ideas ! I feel so bad for him.