Is it a new addition? May take a sec to get acclimated. And don't let it fool you, my leather mush would close up and get a waxy film over it. Apparently they molt and that's their way of shedding. How's the flow in that area? Is it leaning or is it being blown that direction?
The tank is 4 months in the coral is 24 hrs new I had it in one spot where it opened up but bent over to the sand. I moved it to a corner where it opened up again but bent back over . The flow has no effect on it
Then I would say just give it time. They do like a little flow for the molt period to get the "shedded skin" off. Mine just went through a 3 week down time. Bounced back 2-3 days ago better than ever.