Yes, it is possible to reverse gut damage. Gut testing helps to hone in on the specific causes, so that your physician can provide the most appropriate care for your individual needs based on that testing.  Generally, a healthy diet rich in prebiotics and probiotics, taking supplements to nourish the gut lining, and making small lifestyle changes such as reducing stress levels and getting enough sleep, can begin to heal your gut.  Consult with your physician before starting any new regimen.