Bad News! This is not good. First of all, the surgery previously did not fail. There were skin infection right from the start due to the bite. The inner stitches burst because of the pus that's accumulated around the inner stitches. The skin that was used for stitching the inner part were bad skin and there was not enough healthy skin to be pulled and stitch up. At this moment we need to wait for the bad skin on the outside to peeled off and wait for the healthy skin to grow so that it can be pulled for stitching. After that back to the surgery again to stitch the inner wound. According to the doc, he is lucky to be alive till now and currently a bandage is wrap around the 'burst' area. Intestine seems to be working well as he can eat and poop. Hopefully he will recover. This is the best explanation I can explain and thanks to Joseph for writing the explanation as I was not very sure what's the vet was talking about.