Canker sores, also known as aphthous ulcers, are painful mouth ulcers that appear suddenly, either singly or in groups of two or three. They can easily be confused with cold sores. Canker sores are white ulcers with a red rim that most commonly form just inside the lips or cheeks. They burn and tingle, especially … Continue reading Struggling With Mouth Ulcers or Canker Sores?