hf&m or something else?

How old is he and has he had any vaccines?

Have you done the tumbler test? It doesn’t look like HFM as we’ve had it, more like an irritation rash from his nappy maybe x

I'd take him to get checked out, or ring 111 just to be on the safe side. If you're in a part of the country where measles are rising I'd go to A&E, what other symptoms does he have? Cold? Temperature?

Looks like hf&m to me