Soothing the Sting: Top 5 Remedies for Mouth Sores
Milk of Magnesia

Often used as an antacid or mild laxative, milk of magnesia can also provide relief from the sting of mouth sores. It coats the mouth sore and provides a soothing effect, reducing the irritation and speeding up the healing process.
Applying milk of magnesia to the mouth sore can be done using a cotton swab. It should be left on for a few minutes before rinsing the mouth with water.