Blotchy rash on face

[Grommit]

16 month ds has a blotchy rash all over his face but nowhere else. He has no other symptoms. Not sure whether to send him to childminders today. Anyone have any ideas what this could be?
Thanks

could it be a heat rash?
DS went to sleep on his fleecy blanket a few days ago and when he woke up one side of his face was very hot and he had a rash on it.
It subsided that evening

When you say blotchy is it sort of lacy ?