Well, I'm personally hoping stem cells pull through for corneal tissue regrowth. I've got significant scarring in one eye. I'd rather not get a donor (cadaver) cornea sewn on if it's avoidable but we'll see.
I think they're making progress.
The liver is an exception here - you can grow back a lot of it.
Not many times tho: see cirrhosis
Eh? They can grow skin cultures that are good enough to help burn victims. Not, like, with all the pores and follicles being there, but it is skin…