The link is not working but it sounds more like dehydration to me, and wax worms should only be a rare treat food. Silkworms or roaches would provide more nutritional value than a wax worm. Even crickets would be better than waxies. BUt they need greens and foilage to eat too, fruits, veges etc.
How often and how much do you mist him?
What food items do you normally feed?
How do you gutload your feeders?
What do you use for supplements and how often?
What other items do you offer, greens, grapes, fruits etc?
The protusion from the bum, can you email me the photo then I can post it to get more opinions:
dragonflyreptile@aol.com