A canker sore is an oral ulcer (small, shallow lesion) that appears alone or in clusters inside the soft tissues of the mouth, including the inner cheek, or at the base of the gums. Unlike cold sores, canker sores don’t occur on the surface of your lips and aren’t contagious. However, they can be painful and make eating difficult or unpleasant. Though most canker sores will go away on their own in a week or two, sometimes you need faster pain relief. This is why we offer laser canker sore elimination. After a treatment you will experience immediate pain relief, and the sore will completely heal in 24-72 hours. Please note that if your canker sores last longer than two weeks, are larger, or if you feel sick or have a fever while having a canker sore, see your dentist immediately.