I have had the experience that temp can return even after giving Nurofen. I remember asking a doctor about this and he said the body is over powering the Nurofen because the temperature is needed to fight the sickness.

Temperatures are very rarely dangerous and are after all the body's way of fighting infection. (I think panadol, nurofen etc are great though to help everyone get a rest and some sleep and pain relief when necessary - but not necessary just for a temp).

Hope things improve soon.