He looks a very healthy weight, muscular arms + tail.
Will he not eat live food so that you give him baby food ? It's actually a good way to get extra
hydration in him, just add extra water to the baby food once in a while. But he should be eating regular food ideally.
Be sure that your vet has experience with lizards and ask for a write up of whatever he is diagnosed with [ if anything ] and what + how much meds. he is on. One of the mods. here [ Drache613 ] can can read blood tests as well as determine how much meds. should be given if needed.
Also, can you post the exact brand + type of lights you use. what his temps. are and post a pic of his set up ?