Some side effects of a gastric bypass, like problems digesting certain foods and difficulty absorbing nutrients, are well known and treated as soon as you finish the surgery. A gastric bypass hernia is a common complication that may be harder to notice, though no less dangerous if left untreated. If you're experiencing any general pain in your lower abdomen and have had a gastric bypass in the past, remember to make sure your doctor makes sure you don't have an internal gastric bypass hernia. While these hernias are usually easy to treat, one left untreated could become life threatening.