Hi @shann
@Romla's post reminded me of a buddy in NZ who has so many skin cancers there isn't much 'original skin' anywhere as he's had so many removed & plastic surgery/grafts for each ..... one that was on a bony part of his leg was not healing - it had rejected the skin graft & was quite deep & nasty ..... the hospital even tried a 'steam vapour' (continual warm air across the wound) and eventually sent him home.
He visited our holiday shack at the beach & he rinsed the wound every day in fresh ocean salt water. It slowly started to heal around the edges & grew smaller & smaller & eventually closed up completely. He took a 5 gallon container of fresh salt water home with him, to continue the treatment after the holiday.
Other treatments for wounds that won't heal can be Manuka Honey (so SUPER saturated, no bug can live in it) and even egg white! The protein in the albumen coats the wound - and without air - nothing can survive in it.)
I know it sounds a bit 'whacky' - but they've all worked in different circumstances
Maybe mention these to your Drs/specialists - with a bit of luck, one of them might work
All the best for your ongoing treatment xxx