I would definitely offer some paracetamol if he’s constantly crying to see if it offers him any relief. Then maybe see if you can have a look in his mouth to see if he has anything going on like a sore throat or hand foot and mouth etc if he’s not willing to eat. Hope hes feeling better soon x
Definitely sounds like you should try calpol. It's not going to hurt him x
It wouldn't do any harm if he hasn't had any pain relief and is possibly under the weather at all. :)