Another part on mites
The photo above is one of a Bearded Dragon with a case of mites there are a few other places where they will congregate one is inside the corner of the mouth and the other place is under any flaps of skin.
Because I am having this problem I have stripped all the contents out of the cage and hoovered the cage as well and they are at the basics till the mites are gone I'm using printer paper on the bottom which is good to see if the mites are still about and the furniture is fresh logs sterilized water bowl.
Mites can lay dormant for months without the owner knowing then one day they hatch and the problem starts.