The usual course. Moving from sitting to standing, and coughing, feel sore for several days. Bruising and swelling of both groins, and of the scrotum in men, appear around day two or three. It looks worse than it is, and fades over a few weeks. A firm swelling where the hernia used to be is usually fluid, called a seroma. It settles on its own. Draining it invites infection, so it is watched unless it is painful or growing.
Short-lived trouble passing urine is the problem most linked to repairing both sides from behind. The surgery runs across the front of the bladder on both sides. It settles, sometimes after a urine tube for a day or two. It is why you go home only after passing urine.
Lasting groin discomfort is the risk to weigh, more than the hernia coming back. A small number of people have aching, burning or numbness in the groin or inner thigh long after healing. The repair from behind keeps the mesh away from the nerves at the front of the groin, which helps. But it does not remove the risk. Tacks placed in the wrong area are a cause that can be avoided. There is a separate note on groin pain that lasts after hernia surgery, and what can be done about it.
The hernia coming back, stated plainly. A mesh repair of the right size, in the right layer, comes back in only a small number of people. When it does, the cause can usually be found. The mesh may have been too small, or not reached far enough towards the middle. It may have rolled or folded. A second gap on the same side may have been missed. Or heavy lifting started before the mesh had grown in. Smoking, ongoing straining and naturally weak tissue raise the risk, and the first two are in your control. A hernia that comes back after a repair from behind is usually fixed from the front, and the other way round. That is why the operation note on the layer and mesh matters years later.
Less common problems are named, not hidden. The bladder or bowel can be injured during surgery, and this is repaired at the same time. There can be bleeding, with bruising that spreads to the scrotum. Infection is uncommon when the cuts are small and away from the groin. The blood supply of the testis or the sperm tube can be injured, and the testis can swell afterwards. Gas pain or shoulder-tip pain can last a day or two after any keyhole operation.