I'm glad you are starting Actemra and it takes a few weeks, maybe even more, before you will notice a difference. In these past three years as a GCAer I haven't heard a negative from any user I've talked with.

I presented with sight loss in one eye, and they did do a temporal artery biopsy. There was no doubt about the diagnosis and the narrowing of the arteries. Since I was given general anesthesia, it was painless, and the healing was quick with no issues. It is a tiny incision. I've heard of some places 'scanning the artery,' but I'm not sure how that works. It seems the veracity of the outcome is an issue of debate with each side...positive their way is best.
The minor surgery was done by a vascular surgeon because I entered the ER with vision damage. I never went to a rheumatologist prior to that time, but for nine months, doctors (mine, ER, and Urgent Care) kept telling me I had the flu.
I wish you the best and am grateful you have a rheumatologist treating you. There is hope indeed and it sounds like you are on the right track.💞