Follow-up question. How likely is it that this bump on my head is a melanoma?
It could be a cyst, or it could be a mole. It is almost certainly not anything which has to be removed, unless it is mechanically annoying (catches on combs, etc.)
Cysts and other similar bumps can be diagnosed by inspection. In most cases, X-Ray and other studies are not necessary.
When a pilar cyst is removed, it isn't necessary to destroy hair follicles, so a bald spot is not left. The procedure requires local anesthesia, which stops any pain, and takes a few minutes. Removing a mole is even easier.
I would suggest that a skin doctor look at the bump and tell you what it is. More than likely, you will require a very minor procedure, or none at all.
Take care.
Dr. Rockoff