Mouth 'boils' are usually aphthous ulcers (canker sores). For quick relief, you can apply an over-the-counter soothing gel containing lidocaine or benzocaine directly to the sores. Rinsing your mouth with warm salt water or a chlorhexidine mouthwash 2-3 times a day also helps them heal and prevents infection. For pain, you can take over-the-counter ibuprofen or acetaminophen. Avoid spicy, acidic, or sharp foods that can irritate them. If these sores do not heal within 10 to 14 days, are extremely painful, or are accompanied by a high fever, please consult a doctor or dentist for a proper evaluation.