Why canker sores grow in size?

Get it checked: Canker sore typically heal in about 10-14 days and once they form they do not keep growing. If the sore in your mouth is growing, please se a dentist and have it checked. It may be ore than just a canker sore.

Normal: Canker sores are a result of the body not recognizing parts of the mouth as foreign and attack it, until it then realizes that it's not foreign. After that, the canker sore starts to heal.

Canker sores: Vary in size, frequency ; location and we really don't know why. Local irritation may play a role. They start off small when you are probably not even aware of them ; grow in size until your body's defense mechanisms start to heal them.Make sure what you have is actually a canker sore (aphthous ulcer) if it lasts more than two weeks or seems unusual in any way if you are accustomed to getting them.