What causes geographic tongue? is it permanent?

Not really known...: There are several theories that have been proposed for the cause of benign migratory glossitis, aka geographic tongue. Because the condition looks microscopically similar to the pattern observed in psoriasis, some oral pathologists believe that there may be a common autoimmune cause.

Geographic Tongue: It could be genetic, it can also be a sign of trauma, possibly associated with sleep apnea ( a whole 'nother keetle of fish), or other conditions. If it is not causing you discomfort i would not worry but have your dentist evaluate and ask some questions about the possibility of sleep apnea, or others. Also keep the grooves clean by brushing your tongue well. It will avoid infection and odor.