I don't know that he could develop a calcium deficiency in such a short time but I suppose it's possible. Is it the bone of his jaw that looks "droopy' or the skin? It can be hard to tell but if it's the skin it's fine.
The soaking sounds like he might have fungal issues. Does he shed smoothly or is it kind of patchy? or maybe he's impacted and trying to poop by soaking so much. If at all possible I'd take him to a vet who sees herps or exotic animals and who's willing to see a frog. Ruling out fungus would be the best thing to do.