thorsen,
in a separate container with tank water, try cleaning off the base of any loose debris/tissue. i always suggest a separate container because of "milky white fluid". there's other chemicals that are also emitted that are colorless. imo, it's either stress signals or "blood" depending on the coral.
but cleaning the coral of any fungus, necrotic tissue, smothering algae, etc. only helps the coral by alleviating some stress factors. place it in a moderate flow and highlight. hopefully, it'll recover or show signs of recovery within a week.
keep softies away from any stonys or at least keep them "upwind" of the stonys (altho you may see issues with your stonys later like that). but trailing stingers will win over farting softies if the stinger touch. if not, the softies usually win the battle in the long run (you'll likely need significant chemical filtration for peaceful cohabitation). hth