8 min read A FEW WEEKS ago, a story popped up on my news feed about a slug that can sever its own head and regrow another body in weeks. Scientists have theories as to why a creature might want to crawl around disembodied. (I mean, times are tough right now.) And it made me realize that the power of regeneration in nature is kind of amazing. What if humans could harness even some of that ability to regrow, say, healthier skin or fuller hair? In some dermatologists’ offices, this kind of biological magic is already happening. Inspired by natural regeneration, a new crop of aesthetic treatments use blood platelets or stem cells plucked from follicles to rebuild skin collagen and sprout new hair.…