Chemotherapy causes hair loss by damaging fast-growing cells in the hair follicles. I lost the hair on my head very quickly after my first treatment back in September. My eyebrows and eyelashes followed midwinter. I joked with friends that I was constantly surprised throughout the day, but they would never know since I lacked eyebrows.
Some of the hair has returned since switching to a new set of drugs. Still no eyebrows, though, and the hair on my head is thin and patchy like a poorly-watered lawn. There is also a strange dark blotch of "normal" hair on the back of my head that a colleague said looked like the start of a Hare Krishna topknot.
Weird, but no big deal. Baldness is a normal side-effect of chemotherapy, and I will likely keep my head shaved until I finish treatments.