Only wash his bum with cooled chamomile tea.........create a barrier by spreading some egg white on the rash, and then covering it with cornflour......let him have as much time as possible without a nappy..........do you have any nappy rash creams?

If he's really screaming in pain still, I would sit him in the bath with bucket loads of chamomile tea, that might soothe it a bit. Otherwise, yeah, panadol, and lots of cuddles. And don't forget to let daycare know all about it