I wouldnt invest into any of these primarily office/hopd based skin sub companies unless I felt confident that a bigger company would buy them. Mimedx could be attractive for such a purchase because of its institutional market share, payor coverage, brand, and studies, but it would be on the higher end for a purchaser, and the moat for human amnions isnt great. a Solventum or Molylecke could buy a stimlabs for cheaper and just build up.
That said, the other issue is that no one really sells human amnions outside of the US (just epifix in Japan), so while the US market is lucrative, those limit you to one market. And the US market is going to contract at some point due to reform, so that diminishes the shine of human amnios