I know you say you live 250 miles from the nearest reptile vet, but unless you have force feeding or tube feeding experience with lizards, that might be its only hope.
Uros do benefit from UVB, but it isn't as critical with uros as it is with other lizards if they are getting the right diet and supplements. However, a lizard in as bad shape as you describe cannot process food normally until it gets the right fluid level, and the food intake has to be measured carefully, even though it is skinny, or kidney failure can occur. You need to see a vet ASAP if it is still alive for assessment and possible critical care. Then you need to read some care sheets, and you might try to contact Doug Dix and talk to him about rehabbing uros. He has been breeding raising and rehabbing uros for years. Here is his care sheet, and you will find contact info on his web site.
http://www.deerfernfarms.com/Uromastyx_Care.htm
Here is a list of reptile vets in Texas. Maybe you have overlooked one that is closer
http://www.anapsid.org/vets/texas.html
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