I’m pretty sure I once or twice tried sharpening my nail, but I never went too far.
On the other hand (pun intended) I once got the end of my fing the pinched between the pneumatic cylinder and the thing it was actuating. There was a bit of a clearance so it didn’t flatten my digit, but it left a good amount of blood under my fingernail, which hurt a lot. A friend advised me to grab a small drill bit and put a hole into the nail so the pressure is relieved, but it didn’t want to go through… Until it bit in and I drove it maybe a millimeter into my flesh. That hurt even more… But after a while it got way better.