Bummer, looks like it was a beautiful piece. As long as it still has an intact mouth it can be saved in my experience. My go to now for tissue loss is polyplab Primer, seems to stop or severly slow most forms of necrosis. I've had luck with STN, RTN and even brown jelly with this stuff. Revive is also pretty good but it doesn't seem to help with bacterial problems which might be present now with tissue loss like that, but it will get rid of excess dead tissue and whatnot that could be bugging it. I'd give it a good dip in something like those to clean up any junk and lightly feed it if it looks hungry, the extra energy usually helps but too much food can be the opposite. Probably just a wating game besides that though. I only have moderate experience with lobos so maybe someone else has some better tips. Hope it bounces back!