Hernia is the rupture of an organ or tissue in a cavity. It can be defined as "the protrusion of an organ or part out of its normal confines". A hernia occurs when something pushes through a hole or tear in the wall that contains it.
The plastic surgeon is the doctor who specializes in cosmetic and reconstructive surgery.
The oncologist at a doctor specialized in diagnosing and treating cancer.
Remember that for the proper selection of health professional that treats hernia you must consider the nature, severity and symptoms you are presenting.