Docs can you explain what is a canker sore and how do you alleviate the pain?

Cauterization ...: ... Seems to bring the fastest resolution to canker sores. Though inconvenient, treatment of a canker sore with a carbon dioxide laser (many oral surgeons have these) can result in almost immediate relief of pain but complete resolution will still take a while. Local compounding pharmacies also have custom topical products that work well for canker sores.

Canker pain: There are many over the counter medications to help reduce he discomfort of canker sores, however, i recommend you also avoid acidic foods like orange juice, vinegar dressings, tomato sauces and nuts. You can also rinse with warm salt water and suck on Tums (calcium carbonate) throughout the day to help.