1) If you are unsure and really want to know for sure if you have pinworms, do the Scotch tape test. IF positive just treat with OTC Reese's pinworm, I think it is like $8 at Target

2) If you are almost positive that you have pinworms, you can buy the over the counter medicine and treat it yourself. Just double check that you don't have any other associated symptoms (Diarrhea, nausea, unexpected massive weight loss, blood in stool, hemmrhoids, or any genitalurinary track issues.)