defintely not a good sign to see the skeleton, You have a LFS you can go to to get a bottle of revive or coral rx or something similar? Do you have a tank you can use as QT? I would QT that thing and if I couldnt get it locally I would get a bottle of revive or soemthing off amazon with 2 day delivery.
I had an acan that half melted after I put it in, I QT'd it and then dipped in Revive twice, it is now almost whole again and sends out feeding feelers every night.
Otherwise, I am not sure if an h2o2 or fresh water dip would hurt the coral or not.