I just got a bearded dragon, so I don't know too much about their care yet. Still doing research.
I raise box turtles, and if I have a sick one or one who was given to me that doesn't eat, I give it a "baby food" bath. I get some infant carrots, and add some warm water and give them a bath in that. Someone told me that my dragon can have grated carrots and he seems to enjoy them, so I don't think the carrot bath will hurt him and carrots have vitamin A, which should be good for him. Hope this helps.