“How do you shrink a hernia?”

An adult hernia is a weakness in the abdominal floor ; when you strain you notice the defect bulge increase in size, as you relax it becomes less visible. Any activity that increases intra-abdominal pressures will increase the inguinal bulge - coughing, constipation, straining with heavy lifting. Only surgery will repair the defect

Unfortunately, a hernia will not shrink or go away on its own. At best, hernias will remain the same size but more commonly they will continue to grow in size. Repairing hernias early can be beneficial both for the patient and the surgeon. Larger hernias require more time to fix and can be sore for longer.

Surgical repair.

Unfortunately there is no way to shrink a hernia. Once the hole is there it can only be fixed surgically. Over time these can grow larger. It may appear larger or smaller based on how much of the abdominal contents are pushing through the hole. The risk of surgery and long term complications are lower if the hernia is repaired when it is smaller and less complex so I recommend most hernias be repaired before they become larger or become an emergency.
This is general information and your specific case should be reviewed with your surgeon to see how this information applies to your individual situation.