Refractory Skin Ulcer

The goal of this clinical trial is to assess safety and efficacy in patients with with Refractory skin ulcer no response to existing therapy. The main measures it aims to answer are: * Investigation of adverse events * Changes in clinical testing data * Changes in vital signs Participants will have one PAL-222 transplanted to the ulcer site. Researchers will compare before and after the transplantation to see if any safety issues are recognized.