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

The thick, leathery white spots in the mouth that is being produced from smokeless tobacco is called leukoplakia or oral leukoplakia. Oral leukoplakia is a plaque that cannot be rubbed off and is seen in the areas of the gums, insides of the cheeks, and the bottom of the mouth. ;-;
I hope I helped! ^-^

Can you explain it well?