Hello, my mom had knee surgery about a month ago, was in rehab for 2 weeks and now she is home about 2 weeks. I saw her Monday and she seemed under the weather, and here in ny it was beautiful out. But anyway, that night she started with a fever. She has had it ever since, and does respond to Tylenol, but fever has been spiking over and over again. she hasn t broken it. what do you think