Wow, that doesn't look too good. Try moving it to a different place in a day or two if it doesn't correct itself. Granted it was out in this pic it started to retract much like yours, I think it would have died if I didn't move it....also a good indicator is if they start to want to attach to rocks nearby. If they don't they hate the location.
BEFORE
(about a day after this pic it started to retract)
AFTER I MOVED IT TO A NEW LOCATION AND ABOUT A MONTH LATER SAME 2 STALKS NOW ARE THIS COLONY!!!
Its probably split about 3 times MORE since this photo. They are the weeds of corals! I love em!
G/L Though! If they do die something else might be wrong...