A.K.
We just had a similar situation with my 18 month old!!!
I freaked out and was in the Dr office three times getting three different opinions as to what it was. The only consistency was that it was nothing to worry about and it would go away. She had hers in total for over a week with the worst of it being toward the end with fevers.
IT WENT AWAY! *lol
If you go online there's only one rash (looks like a red pen point on skin) that's bad, so try to be calm and don't freak out like me :) I think the heat makes any simple rash look worse than it is. I hope this helps :)