People addicted to smokeless tobacco can develop thick, leathery white spots in the mouth. what are these spots called?

Hello! This is pretty common with smokers, some get other effects, however, this one is most common! This is clinically known as leukoplakia. leukoplakia is the thick white patches inside the mouth. Some of the patches could also be a sign of cancer and should be checked out by a doctor. 

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SuperHelperThingy