He is not feeling unwell.
Infact, I was getting him changed to go to his friend's swimming party when I saw the rash all over his chest and tummy, some on his back, some on his arms, and some round his mouth!
Poor little chap is distraught that he can't go to the party.
I've been through the NHS symptom checker and am confident its nothing serious, it looks most like hives. I can't understand where they have come from? He has been absolutely fine all day, no trace of a rash this morning.
Do I need to do anything, do you think?