What Could Painful, Sore And Hard Knot Behind The Scope Invsion Post Appendectomy Be?

My husband had a ruptured appendix four weeks ago and had an open appendectomy.Two weeks later he had an abscess in his groin. He just got the drain tube out four days ago. He has a hard marble or pea size knot behind one of the scope invisions that was made during second surgery. He says it hurts and is very sore. Could this be a hernia?