Usually canker sores heal on their own within 7 to 10 days. To alleviate the pain associated with it, you can apply gel such as oragel, orabase or mucopain. Sometimes the sores are accompanied by fever and body-ache. If so, then you should take appropriate medications to control fever. Avoid eating spicy and hot food and drink a plenty of water.
It should subside soon.If you don’t see improvement withing a couple of days or the sores increase in size, please visit your nearby dentist.