Hi Katie.
Thanks for raising this question. I am also in the same boat with a large bald spot on top of my head. Rest of head is OK bit patchy on the left. I have had a couple of colours put on to "bulk out" the hair. I am charged a reasonable rate which is good but unfortunately in the computer it is called "Colour - Men's short back and sides". I am considering using Regaine - there is also a women's version. I am only 4 months post AC so still optimistic. My left eyebrow and left eyelashes are also showing no signs of coming back. My (second) oncologist has said it may be permanent but no-one said so at the start. That adds to the distress I believe. I might have thought about cold cap if I had known (although it is not offered at the hospital I went to). All the best.
Helen