Okay, bumping this to update, and probably will a few times again over the next year to log my experiences.
It's coming up on three months now, and the whole numbness experience is pretty okay overall, but, well, yeah, still numb. However, I'm starting to be able to feel just a little bit. If I tap gently, I can sort of feel in the skin on my scalp where I'm tapping, and it kind of tickles. If I poke myself with my fingernail in a manner that would hurt elsewhere on my scalp, I basically feel nothing. But the feeling I get with the taps is encouraging that maybe it will come back.
There's no specific area that I can feel more or less. It's all just uniformly numb, except that when I tap near the edges of the numb area, it causes a slightly sore feeling rather than the tickle I feel when I tap more toward the middle.