Hi, can't help you out with the swelling, but I gave you a link to finding a vet. I tried it this way but the one listed in my area wasn't too close so I called my "mammal" vet and she gave me a name, too.
:I noticed today that my veiled chameleon has a large swollen looking bulge on one side of his vent. 2 questions.. Does anyone know what could be wrong? What is that website where you can find a herp vet in your area?