It is not true regeneration, like a crab growing back a whole torn off claw, but more of a reattachment. It ranges from minor stuff like small cuts in the kitchen, where skin connects to itself to close said cut, up to whole freaking limbs getting torn off and reattached with whole muscles and bones and arteries and nerves reconnecting again into a complete whole.

Could you imagine how fucked we would be if our bodies could not do that?

Every day you would have to disinfect and wrap your hands and feet in fresh bandages so you don't bleed to death. Imagine disinfecting multiple square inches of flesh if you survived a deep cut. Burned? Untie the large leather sheet covering your burned skin and apply medical ointments. Broke a bone? Unwrap the giant V shaped access groove, remove the cotton stuffing, untie leather straps that keep your flesh somewhat in place to inspect the copper tube attaching your two bones with nails. Same would go for cut veins and arteries. Not to mention the external metal fixtures which, like an exoskeleton, take on some mechanical strain of your movements, you got to maintain those too. People would look like plumbing fixtures.

In modern times I imagine a lot of holes in muscles would be filled with either rubber or glue, just for some kind of permanent insulation of exposed flesh from outside bacteria, viruses and mechanical forces. Each of us would be covered in bottle cap-sized clear plastic buttons that protect small cuts and punctures. Some would have their whole limbs encased in plastic.