Hi... Thanks for the query... As per your history of tobacco chewing in past and smoking the white marks on the inside of cheeks can be due to LEUKOPLAKIA which is a Precancerous lesion and is formed due to overproduction of Keratin causing formation of hyperkeratotic patches on the cheeks, lips, tongue, lips, palate and occurs due to persistent irritation.. It mostly resolve once the irritation is removed permanently.. You should completely stop smoking and chewing tobacco and apply a Steroid containing ointment over the inner cheeks, take beta-carotene supplements which are precursor of Vitamin A, take Multivitamin supplements, take anti-oxidants like Lycopene.. Hopefully the lesions will start resolving and in case of no improvement a biopsy can be done to rule out the severity of lesion and surgical removal can also be planned accordingly.. Hope this helps.. Regards.