Hello,
This is a fascinating thread for me, I hope to find more of the same. When I was 34 I had
R parotidectomy for acinic cell carcinoma. The margins weren't clear, the tumor was spreading into my face. I was given 2 choices: go back to surgery in 2 weeks, or radiation treatments. Now I realize I had terrible anxiety and couldn't face surgery again, I chose radiation.

As @sepdvm says, these symptoms are gradual and ongoing over time. I lost all of the hair on the right back of my head. This made me realize my brain was involved. I have other health issues that might affect brain fog. I think my way of dealing with that is to push myself. Maybe that is what @sepdvm meant by brain plasticity. I lost my career as an RN in oncology and became a poet and yoga therapist. My biggest difficulty has also been hearing loss on that side and last year I got hearing aids. I have a challenge with tinnitus and have been told it is from damage to the nerves in my neck.

I also have lymphedema on that side of my neck from time to time. I went to a specialist to learn self-massage. I have incorporated my disabling chronic illnesses into/not separate from my life. They inform me but do not define me.
Thank you to everyone for their helpful comments.