Well,you did a good job saving him and getting him to eat....so until he's fattened up,let him have it his way.Who knows what the starvation did to him....maybe his tongue does not extend,maybe his eyesight isn't great.Keep his food supplemented as well....is your vet a reptile vet? If not,you could waste your money if HE [ or she ]doesn't know chameleon anatomy either.