39.5 degree celsius fever last 24 hrs still going. does come down with panadol (acetaminophen) but goes back up. also headache, runny nose and lethargic for 4yr old. ?

Probably a virus: Hello. It is reassuring that your daughter's fever is responding to the panadol (acetaminophen). That makes a serious bacterial infection unlikely. The fever may go up again when the panadol (acetaminophen) wears off. Most viral infections have fevers that last 3-5 days. She may feel achy and have less energy when the temperature goes up. If new symptoms develop or the fever lasts over 3 days, she should see her doctor.