Torches as well as frogspawn and hammer can be sensative to tissue damage. Any of the several things you posted that have changed could have stressed it, You can do as yote posted and find some type of coral dip, in my experience time and patience is the best solution. I would make sure it isnt getting alot of flow blowing against the tissue. If you do move it dont touch the tissue, try and only handle the old skeloton. If you increased the light output try shading it and slowly bringing the coral into full light again over time. There isnt in my opinion alot you can do, and trying to many things to save it is usually more stressful than just finding a good spot for it and leaving it alone to heal. If the dieing heads start getting a brown jelly like coating over them you can blow it off, but that is usually the last stage before it dies. Good luck and let us know how it goes