TMI.. what is this?

So this little spot type things have just appeared tonight under my boobs, belly and my groin area, they’re quite itchy and I’ve never had them before, what could it be? It’s not from changing laundry products I know that. Pic of under noon they all look the same on the other parts I’ve mentioned. I was thinking maybe sweat related as my flat is quite hot, what can I do for these to make them go?