If you're in Utah, there are at least three different doctors listed in the resources below.
Note: I haven't personally verified the legitimacy of the sources below.
Clearly doctors not considering PANDAS a real thing is still an issue given the question at this first website.
"What if my child’s doctor does not understand or does not want to consider PANDAS?
Contact the International OCD Foundation or the PANDAS Physicians Network to find a doctor who may be knowledgeable about PANDAS."
PANDAS - Questions and Answers (National Institute of Mental Health)
PANDAS Physicians' Network
https://www.pandasppn.org/
Support Groups (likely to have good, current information):