Ouch! Lots of people get mouth Ulcers. The word, ‘ulcer’ seems big & scary, but there’s help for what so many people will say, “I’ve got this this little irritating sore, right on the side of my cheek”. Mouth ulcers happen to more people than most think. In fact, recurrent mouth ulcers occur in approximately 20 – 40% of the U.S. population.