Actually I just looked and it does have an open mouth and it has some whole stuff coming out but it’s not stringy kinda looks like intestine’s if that makes sense?
Sorry I'm so late to the thread. But I wouldn't have given any other advise than what was given. At this point, since it's not holding on to the rock, I'd pull it from the tank and put it in a small bowl or Tupperware container. Do a water change from the tank 2 or 3 times a day. These guys are kind of hardy and may still make it. But it could also be injured and may not make it.
I wish I could be more help. Keep us posted and I'll follow as well.