S.L.
Zyrtec is what they suggest for hives if it is hives and although it won't help the fever it should make him feel better. I just had a 'bug' and got splotches like hives and the Zyrtec helped with that. I think maybe it's allergy though but check with his age first to see if it's okay to give him. Is it like a fine L. rash of bumps and also red splotches? That's what I had and after the Zyrtec for a few days it's gone...for good I hope. Hope he gets better soon.