I've lived with varying degrees of mTBI for 60 years with many concussions and mTBI events since.

My first impression is you expect doctors to fix you. That is rarely the case, especially with neuros. I've never gone to the doctor for a fever. Maybe that is a generational thing.

You only mention headaches but nothing else. How is your sleep? Do you have any neck discomfort or limitations?

Whiplash and other cervical trauma is present in over 80% of concussions and MTBIs.

Without more information, I can't offer more help.