Oh man, that's not good. I don't know what that is. I'm sure it's not coming through well in the picture. You would know if it's a heat rash.

I probably would have followed my same procedures for my kids and let clients know last night that you have a rash geting worse and they can send their child at their own risk as you're not sure what it is. However, now that they're there and you have them, no sense in sending them home if you are able to care for them. If it's catchy, they've probably caught it.

i hope it's a simple solution and you feel better soon.