What happens if I leave my constipation untreated?

Constipation. At minimum, you should see a doctor and have a colonoscopy. If this test is normal, then the question is what exactly are your symptoms, and what is the frequency, severity, and impact on function of these symptoms. If constipation cause you to not eat, lose weight, and become ill, or if you cannot work or function socially because of these, it should be treated.
Problems. Constipation that is not treated in children can cause irreversible damage to the colon. Long term this will effect normal function and quality of life.