I have a tongue ulcer that is white around the edges asnd there is a depression in the mmiddle. i do not smoke or drink. should i worry?

See a dentist. : You need to see a dentist/ md immediately for proper diagnosis and treatment. Fortunately, the majority of tongue problems are not serious and most can be resolved quickly in some instances, though, a discolored or painful tongue can indicate more serious conditions, including vitamin deficiencies, aids, or oral cancer. For this reason, it is important to seek medical advice.

It depends: It depends on how long you have had this ulceration. Most tongue ulcers are nothing to worry about and heal within 2 weeks. If you have had it longer that this see a dentist, oral surgeon or oral medicine specialist for an examination.

Worthy of concern.: Without a good history and exam + biopsy, it is difficult to say for sure, but the lesion you describe is worthy of a workup. While the traditional head/neck cancer is in a smoker/drinker, this is changing with the emergence of the hpv virus (virus also causes cervical/anal cancers). If the lesion persists more than 1-2 weeks definitely see your pmd/ent/head ; neck or oral surgeon.