2. Mouth sores  (Trust Mark: Doctor-Reviewed)
Various types of sores can appear anywhere within the mouth, including the inner cheeks, gums, tongue, lips, or palate.• Reviewer: Robert Hurd, MD, Professor of Endocrinology, Department of Biology, Xavier University, Cincinnati, OH, and physician in the Primary Care Clinic, Cincinnati Veterans Administration Medical Center, Cincinnati, OH. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

3. Pain  (Trust Mark: Doctor-Reviewed)
Pain is a universal human experience. The International Association for the Study of Pain (IASP) defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage."...• Author: Rebecca J. Frey PhD