Sounds like tissue nurociss which attacks and eats away the flesh of your coral what I have done to cure this problem is make a freshwater bath the same temp as aquarium and dip untill brown jelly is gone.The fresh water kills the bacteria, then place in a moderate to high current and if possible low to modurate light.The higher current will help to stop renfecttion but I have to say this is still a 50/50 chance goodluck and I hope this helps.