Rashy botty - what is this?

[Essie3]

My baby has a rash on his peachy bum. It's all spotty, like he's been in nettles (he hasn't ). It's all over his bum cheeks.
DS is 5 months, exclusively bfed.
I, however, have been on penicillin for the past 4 days. Could this be the problem?
And how can I make it go away?

hi essie3, does it look something like 'prickly heat'? That's what I get when I take certain antibiotics...

But it could also just be a simple case of nappy rash

Best to check with your GP if you're concerned and lo is in pain or discomfort