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What Are the Symptoms of Canker Sores?

Symptoms of canker sores may include:

  • Tingling or burning in the mouth; this sensation often occurs 6 to 24 hours before a canker sore appears.
  • Round or oval ulcers that are small and painful
  • Sores that appear singly or in clusters on the inside of the mouth, including the inside of the cheeks and lips, on the tongue, at the base of the gums, or on the soft palate
  • Sores that usually heal within 5 to 14 days without scarring
  • Sores that are grayish white or pale yellow with red borders

Call Your Doctor About Canker Sores If:

Medical Reference Reviewed by Tyler Wheeler, MD on March 28, 2019



The Mayo Clinic. 

National Institutes of Health. 

Goldman’s Cecil Medicine, 24th ed.