Oh, and to be a lawsuit, there has to be negligence. Even a lot of mistakes don't qualify as negligence, and this might not be a mistake.
Are you sure that's what he said? Sometimes with hernias, they have to place mesh and during healing you will get a bubble of fluid that is on the surface of the skin and has to be drained. It is a normal part of healing because of the mesh, and doesn't signal that anything is wrong. I don't know if this happens with inguinal hernias or if you had mesh, but it was a thought.
Or did he say there was a re-tear?