Redness on inner cheek. no pain. but white filimy substance on that effected area. painless and no complications?

A couple of thoughts: The first is yeast/candida. White film may occur, more likely on the tongue, with a fungal infection in the mouth. Usually there would also be burning. Occurs as the result of antibiotic, oral steroid use or immunodeficiency diseases (HIV). It could be leukoplakia, a chronic irritation of the mucous membranes from rough teeth, smoking. See your dentist, oral surgeon, Ear/Nose/Throat specialist.