Have you seen your dentist lately? Not to make you worry, but any patches or sores in your mouth that don't resolve themselves in a week or two should be investigated. It's pretty simple: your doc or hygienist will shine a special light on the area. Depending on how it reflects the light determines the next step. Yes, these can be serious and can be cancerous. You may need a biopsy or be sent to an oral surgeon for the biopsy. Physicians do not work in the mouth, but we in the dental profession spend almost all our time in your mouth. Best wishes!