I had 30 sessions of FSR this summer and had very few side effects.
About 4 weeks into my 6 week treatment, I had some fatigue, but I just let myself rest when I could, especially on the weekends
I also had some very mild nausea--more like a constant sense of indigestion--and my doctor had me do a short course of a steroid, only for a week or so.
I do have a couple of small bald patches, behind my ears, the larger one on my AN side (I just discovered the other smaller one a few days ago.)
Otherwise, though, I feel great. The fatigue and nausea ended as the treatments ended. I am fortunate in that my hearing has been only slightly impacted and my main symptom has been mild numbness on the AN side of my face. While it's mildly annoying in my eye and my mouth, otherwise I don't notice it that much.
I will have my follow-up MRI sometime in the spring, but so far, so good.
Good luck!