Mouth ulcers are very common and usually heal on their own within a week or two. To ease discomfort, you can apply a topical pain-relief gel containing lidocaine directly to the sore. For inflammation, a generic corticosteroid dental paste, such as triamcinolone acetonide, can be very helpful. Rinsing your mouth with warm salt water or a chlorhexidine mouthwash also keeps the area clean and promotes healing. Try to avoid spicy, acidic, or crunchy foods that can cause irritation. If your ulcers persist for more than two weeks or are extremely painful, please consult a doctor or dentist for an evaluation.