After removal, the appendix is sent to a patho-hystological laboratory to confirm the diagnosis for "appendicitis". There are many cases when a healthy appendix was mistakenly removed. Diarrhea is not typical for appendicitis but is the main symptom in ulcerative colitis. A colonoscopy with a biopsy can confirm or exclude ulcerative colitis. Microbiological examinations of the stool are also requested to exclude intestinal infection. It is difficult to tell if the erosions in your mouth are related to the gastro-intestinal condition, or not. Both are possible.