I had bought (knowing they were bad) 2 uro's from a pet store an then turned them in for neglect. Happy to say that we won that case! 
But the one, was even thinner than the one you have. There was NO meat whatsoever. NONE. Just skin hangin off of bones. Very very sad. Fortunately, he has healed and now is quite plump and happy
. The other one, was in such bad shape from being stuck laying a a soaking wet sand with no heat source or fresh veggies, that the scales on her feet rotted off as well as a portion of her underside. She was just rotting away till her skin was smooth and swollen. We were totally amazed that with daily treatment and therapy on her one foot, that she regained total movement of it again. Unfortunately she died earlier this year of unknown causes
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So yes..abuse is not something I am not aware of. Very sad..hope you can get him eating soon! Highly suggest some force feedings of baby food right away with vitamins mixed in. could possibly help save him!
good luck!
Renee