DS had his a couple days ago. For hours afterwards he would briefly doze off then wake up screaming his head off again. I'd never seen him so upset. Lots of cuddles and by early evening he was back to his usual self. (Though he still looks panicky whenever his pants come off :/)
He slept much longer stretches than usual that night. We got liquid paracetamol for him in case he had a fever but we didn't need to use it.