A "canker sore" or aphthous ulcer is usually painful for the first 4-5 days and heals without treaatment in 10-14 days. For severe outbreaks with numerous lesions a Tetrcycline Suspension may be indicated and /or topical lidocaine combined with both systemic and topical corticosteroids. See your doctor ASAP if you have a severe outbreak. A red papule that develops into a painless ulcer can be a symptom of Syphilis. There are multiple other ilnesses that can cause simlar symptoms, without a history and physical exam an accurate diagnosis is impossible.