What is this skin infection

Hello! My kitten whose 11 weeks starting having bumps all over his skin. Took him to the vet and the vet said it’s a skin infection but not clear what it is. He was given antihistamine and antibiotics (is currently on second day of 5 days antibiotics) Today some of the bumps popped and you can see red skin exposed. I’ve attached pictures of some of the bumps (popped and unpopped) I’m curious what exactly it is if anyone knows. Thanks 

Hello!  I'm afraid that I can't safely diagnose a pet from these photos, even if it were ethical to.  However, I wonder if your vet suggested any tests to find out?  It's unusual for a vet to say 'I don't know' and leave it there.  How was the rest of the examination? Did they perhaps think that swabs / biopsies / referral to a dermatologist are worthwhile?

Hello!  I'm afraid that I can't safely diagnose a pet from these photos, even if it were ethical to.  However, I wonder if your vet suggested any tests to find out?  It's unusual for a vet to say 'I don't know' and leave it there.  How was the rest of the examination? Did they perhaps think that swabs / biopsies / referral to a dermatologist are worthwhile?

The erosions left behind look to be deep and potentially sore - it's well worth calling your vet to let them know of the new development.