How do you know if you have burning mouth syndrome?

Rule out all else: Burning mouth syndrome is a "diagnosis of exclusion" which means that many things that cause similar symptoms must be rule out. This requires seeing a doctor who specializes in oral disease (often a specialized dentist or specialized dermatologist). Have it checked out.

By Symptoms Only: There is no test for burning mouth syndrome...No blood test, dna test, or any other. The diagnosis is made completely by history & symptoms, which can vary from person to person. Like with many other conditions, you need to rule out all other possibilities, and then accept what's left as the diagnosis. It's important to have your dentist rule out other conditions which have similar symptoms.

Burning mouth: You feel like your mouth is burning and you haven't just eaten hot pizza.

Well, what you got?: If you have a scalding sensation in the tongue, lips, palate, or throughout the mouth, and if you have the burning sensation that begins in late morning, builds to a peak by evening, and often subsides at night, if you have any of these symptoms then you might well have bms and should seek help. Please seek advice from your dentist. Best wishes.