Hard to tell for sure from the picture. Fromia stars don't have a good survival record in our tanks. Often they're goners before you even buy them, looking fine for a while then just disintegrating. Not much to be done, it will either survive or it won't.
I dont think you can save it but at least let it die in the aquarium.After she dies you can take it out so it wont cause you an ammonia spike.These stars have litle survability rate,they need long time aclimatisation .If she would have passed the aclimatisation shock then in a year or so it would have died by starvation because theyr diet is unknown.If you want to have a seastar ,then the serpent stars are the most resistant.Serpent stars arent as beautifull as fromia but they can live verry long time in aquarium.