Incidentally, I noticed that in another thread you post that you've seen some black hairs appear from a cleared, previously all white spot.
Some electrologists also say that hair growing from a previously cleared spot occasionally gain color. I myself have also seen previously white hair periphery to a cleared area grow darker. To paraphrase what I've read elsewhere, skin is evolutionarily well equipped to handle puncture wounds, and reacts to them with local histamine release induced inflammation that in turn increases circulation and collagen generation.
This sounds similar to the effect induced by skin-rejuvenation treatment with spiked "dermarollers" and their ilk. Since each individual trauma is so small the healing is practically three-dimensional and there is no scarring, but the skin does go into repair mode, and the emergency signals in a sense call previously dormant reserves into action.
