If he implanted it himself, that would imply impressive surgical skills
edit: paywall bypass https://archive.ph/CCXpf
edit: paywall bypass https://archive.ph/CCXpf
Funny story, I dealt with a pylonidal cyst on my tailbone by myself. I did not expect that much blood tbh (along with very stinky puss... sorry for the detail), but I managed to drain and clean it.
Apparently you need surgery for those... it really wasn't that hard, cutting in was the hardest part, but at that point the pain from it was worse.
I do hate it when cats come out of infected spots.