6-8 year old yellow throated plated lizard-male we think

Question
Our yellow throated plated lizard has been going down hill for about one month, has not had any energy and seems to be impacted as we have seen no feces in his tank and today he was wriggling around and having so much trouble.  WE did put him in some warm water for awhile, maybe we need to more.  WE keep him in  ground up corn cobs as bedding and have since we had him- he always would dig and hide now he doesn't have the energy to do that either.  He has lost maybe half of his body mass.  
We live in an area that has very few vets that will take care of exotics and our pet store in the area seems to not want to give any advice maybe because of liability,
any suggestions???

Answer
The corn cob substrate should be thrown out, the pieces are sharp and not only can he become impacted by ingesting it, he may be suffering from lacerations in his digestive tract. You may have to travel to a good reptile vet.  You can refer to www.arav.org for a list of veterinarians that specialize in reptile care.