The most likely diagnosis is that this is lichen planus it is a lesion that is relatively common it is not malignant and has low conversion to a malignant lesion. We are NOT certain what causes lichen planus there are many theories such as it is linked to auto-immune disorders, contact dermatitis from adjacent silver fillings, stress induced, and even dietary nutritional deficiencies such as iron/folate deficiency and vitamin B12. A definitive diagnosis can ONLY be determined by doing a biopsy of the lesion. There are several different classifications of lichen planus and one type often appearss as a white filmy almost spider web appearance on the oral tissues most commonly on the cheeks, these are known as "Wickam's striae". Often patients complain of discomfort when eating acidic or spicy foods so a bland diet is recommended. It is not uncommon for the lichen planus to disappear spontaneously. As far as medications sometimes oral topical steroids are prescribed or steroid rinses as a palliative treatment.