A picture is really needed here. without the picture I can only suggest keeping it in a low flow area away from any other areas with good lighting, then leave it alone for a few days. If you think it's too far gone and dying off then the other option would be to try and frag any healthy tissue and getting it to grow on some rock. fragging can be accomplished by using a sharp pair of scissors or a razor knife and cutting a healthy looking piece from the body. You can use rubber bands to wrap around the piece and secure it to the rock. leave it at the bottom of the tank in a low flow, well lit area and if healthy, it will attach itself to the rock. It may take a few days to a couple weeks for it to get secure on the rock.
sorry I can't be of more help
Tivo