I really can empathize. I had brain surgery and both where they took out the tumor and where they put in a drain (sorry if TMI) I don't have hair and my hair is thin to start.

Your situation, I'm sorry to say, actually sounds worse because it's in the part. Can you part it on the other side? Or do a style without a part?

I hope it turns out that the surgery is minimal. Please post back! BTW, I have found that coloring my hair makes it thicker, so if that is an option for you, think about it. The permanent color coats the strands.

Good luck!!!
2/c and some 3A.
Protein sensitive but can use occasionally
Highly porous. Color over grey.
Best 1st day method: Super Soaker
Stylers: Mix Curls in a Bottle into everything for shine. Terrible pj
Sometimes try roller sets - classic glamor but I prefer my curls.
Every day is a gift