Diarrhea with slapped cheek? (Rash pic)

[FainaSnowChild]

My 12 year old was ok yesterday til lunch then sudden high temp and sore throat. Was 38.7 2 hours after paracetamol. Then it went down and it was fine this morning (36.7), he says his throat feels dry but not too sore now, but he has diarrhea. I noticed this rash come up on his cheeks late last night, it's not as bright red as in some online pics of younger children but I wondered if as he's 12.5 it might not be as obvious? No rash elsewhere yet.
Picture not super clear unfortunately, it's a slightly rough feeling rash.

It’s likely to just be a viral rash the mention of it being a rough rash made me remember that scarlet fever is doing the rounds in the U.K. probably not that but a possibility.

Keep an eye out for rash spreading to chest / back etc. Especially around neck / armpits / groin.

We've just had a diagnosis of scarlet fever here which needs a 10 day course of antibiotics