White ridge on one cheek up to my lip.

Its highly impossible to tell anything without proper clinical evaluation so better visit ur dentist. But according to your description it appears that u may a high point one of ur recent filling so need to check it with ur dentist. Do u have any habit?like chewing tobacco or guthka? White line is probably due to linea Alba which is nothing but an imprint of ur occlusion line.so don't worry about that.

just visit the dentist to rule out any high point in ur recent amalgam filling.

It is difficult to provide a rational suggestion without a look at the clinical condition of the teeth and the affected area. If it is Linea Alba, it is nothing to worry about because it is just frictional keratosis in an area where there is continuous mild trauma. The diagnosis of lichen planus cannot be established without a biopsy, and the symptoms also will be different than what you have described. Acid Reflux can cause damage to the teeth but not such symptoms on the soft tissues. And all these are tentative suggestions based on your description. If there is a sharp edge due to a filling or of the tooth, it can be corrected by the dentist when you make a visit. Please consult an oral pathologist if possible for a proper clinical evaluation of the case. Regards.