Does the vet work with chameleons though? Some vets might know other reptiles but not know much about chameleons. That does make a big difference.
There are other young chameleon keepers here who have learned from the forum and shared threads with their parents to help them understand the importance of quick intervention and vet assistance. That might help you as well.
So say you don't take him to the vet and he does have an RI. Popping can be a tell tale sign of an RI. The chameleon will get worse, and as he gets worse, his chance of recovering from the infection decreases.
So you do take him to a good chameleon vet. The vet either confirms RI and prescribes antibiotics. Atlas has a better chance at recovery. Or the vet says it's something else or something benign. Then your chameleon has had a wellness checkup, which every pet ought to have on an annual basis anyway so the vet can keep an eye on your pet's health. Plus, you could bring in a fecal sample and get him tested for parasites too.
Going to the vet might be inconvenient or costly at times but ultimately worth it given the benefits of going versus the risk of not going.
Hopefully
@Beman and
@kinyonga and
@MissSkittles and others will chime in soon as well.