Hello Jen,
Our dentist just this past year started doing the test you menioned with the dye and light. It's a mouth wash you swoosh around for a minute and then they look around your mouth with this special light. I believe it just shows abnormal cells which would then cause them to immediately send you to the Dr's. It was actually our dentist who sent my husband Kyle to a Dr. after noticing the lump in his tongue. He probably bought my husband many years of life by catching his cancer early! He's got 3 days left of rad/chemo. I would not stress out however, it could be anything. Good luck. Tammy (Kyle 51's wife)