This sort of thing isn’t as uncommon as we’d like to believe. People wake up with the wrong leg amputated and shit often enough that people going in for procedures often write on themselves in the hopes of preventing it (links to examples below). And apparently doctors ask you to mark off which side sometimes on your own.
With the sheer number of surgical procedures every year, it’s basically inevitable that mistakes and fuckups will happen.
Now the cover-up part.. that’s a bit more unusual.
https://tse3.mm.bing.net/th?id=OIP.ps7uAGc7LoIg6KBkwJGuCAHaJ4&pid=Api
https://tse3.mm.bing.net/th?id=OIP.l6EFuD7rpjfu3aPqoAs38wHaHa&pid=Api
https://tse1.explicit.bing.net/th?id=OIP.7m8gYb6oBQIFNlaKLklhkQHaEs&pid=Api (This one reads: Remember, not the whole knob, just the foreskin)
I live there and I had no idea 😅