the bands are sufficating the flesh, shove the peices of coral in the sand if its big or leave it in a corner so you dont loose it, then aim a fair water flow towards them enough to airate but not too hard to blow away, make sure you give it lighting, if you have a small plastic dish fill it 1/3 with sand and place the corals on it, then place the dish where it will get flow and light.
Give it a few day for the coral to recoop, it may take a while for it to close the wounds and start to regenerate, I wouldnt glue at this time, wait till regenerate, and heal, if not the flesh may just continue to melt at glue point because its so weak. healthy toad stool's flesh will be dry and leathery when immediatly out of the water, if its slimy then that part its dying, Finger leather coral is harder to manage becuase that coral is slimmy all the time,