That looks like a giant pyxie that has a lot of issues. Where do I start? If the frog is 6 years old male or female that is grossly undersized as your probly well aware of. He probly didnt recieve proper diet, proper digestion, or proper feeding frequency. As for the yellow spots on his side it looks like a fungi. does it rub off at all? I'd soak him in chlorinated water, like regular sink water or bath water it will do him some good to be honest. His appetite is probly horrible at this point, I would just make him/her as confortable as possible... I condone you for picking him/her up from the show because that is absolutely ridiculous