What happens if I don't get surgery for my hernia?

Depends. Untreated hernias can enlarge or cause bowel blockage.
Same or worse. They don't go away, or better by themselves. May not progress. Elective surgery for hernias (inguinal/groin, femoral, abd wall-incisional, spigelian) that cause symptoms. If hernia gets bigger, gut can get stuck (incarcerated): urgent surgical repair. If gut gets stuck and blood supply compromised ("strangulated"):surgical emergency. Usually younger is better surg risk vs older. Truss nonsurgic.
It depends on... ...Type of hernia, it's size, symptoms, and findings on examination. In general, many small hernias that are not causing symptoms may be watched, however they will never go away without surgical treatment. I recommend that you see a hernia surgeon to learn about the pro's and con's of surgery vs. Observation.