Gail, I had a very unstable temp like that for about two weeks following the end of rad and chemo. They kept me in the hosptial for a week and 1/2 just to be safe--because I was also neutropenic when they admitted me--but they never really located the cause of the fever down to one specific infection. When I was admitted the burn on my skin was very inflamed and peeling and they thought that might eb the cause, but they treated that with sivadene cream and the spiking fever persisted long after the skin had peeled off and the neck ahd healed. So I never really knew what it was due to but they ended up concluding they'd eliminated all the bad stuff it could be and I wasn't neutropenic anymore so they sent me home. By about week 3 out of rad/chemo the fever disappeared.