Take it home and acclimate is very slowly, because you don' want to stress it out more. Put it at the bottom of your tank on the sandbed. And give it a week or two. If it looks as if the tissue is still dying then I think that is is on its way out for good, but if the tissue begins to show some signs of regeneration then I would keep it and give it some more TLC.
Hey rocko. I am not that slow. B)