It could be one or a comination of things. There is fractional keratosis, caused by friction, injury, but this and leukoplakia can't be rubbed off. Leukoplakia, is often confused with thrush, which can be rubbed off. It can also be lichen Plantus, Thrush is treated with anifungals. Leukoplakia also does not mean that it will always transform to cancer. But can 1-20% of the time, up to a span span of years, up to 30 years. As David suggested, see an ENT. Good luck.
