I have cracks on my tongue and it hurts?

Geographic tongue: Geographic tongue is a genetic variant where large furrows in the tongue occur. Glossitis or inflammation of the tongue may be present in these crevices. Causes of glossitis include vitamin b deficiency, and fungal infections. If you are a smoker, have an oral surgeon or specialist in oral medicine evaluate your problem.

Dry mouth and/or: Candidiasis (thrush) are two good possibilities. Your dentist should be able to give you a more concise diagnosis and prescribe proper treatment. It is not possible to diagnosis your condition with out an exam.