M58, found a white patched slightly raised painless small ulcer (3 mm dia) round in shape in between left jaw and cheek. what could be this? thanks

? Canker Sore?: Ulcers can form inside our mouth and do so, often. Many of them are caused by viruses, often difficult to even diagnose...So these are called canker sores for lack of any better definition. Fortunately they heal, on their own, within one to two weeks. If it keeps growing in size and has not healed within 3 weeks, you should go see your family doctor( or a dentist ) to check it.