I still have the evidence of my stupidity when I about blew my finger off almost 50 years ago.
I made a cannon barrel on the lathe in 8th or 9th grade metal shop, still have it too.
When I got the cannon home, me and a neighbor kid decided to load and shoot it. We went out to the workbench where my Mec 600 JR was mounted and dropped some Red Dot and then funneled it into the cannon. I would guess it was 70-90 grains worth. Having watched plenty of TV we “knew” the gunpowder HAD to packed before adding the projectile. I stick a Philips head screwdriver down the barrel and hold both the cannon barrel and screwdriver vertically. Then the neighbor kid starts whacking the handle of the screwdriver with a hammer. Just as the word “STO...p” was coming out of my mouth, you guessed it, KABOOM!
The kid started crying and immediately bolted for home as fast as that shaft from the screwdriver blasted through the plastic handle and through the ceiling. The kid wasn’t hurt, just scared to pieces. Meanwhile my hand feels like a combination of numbness, intense stinging and burning. The base of my middle finger looked like blackened hamburger. The opposing fingers had superficial wounds.
We went to a new hospital close by, but they couldn’t handle it, so they sent us somewhere else. I just remembered the intense pain that lasted for days (and back then they didn’t give pain pills to kids, even in later years when I broke my wrist twice). I don’t know how they repaired without stitches, there was nothing to stitch. But it healed eventually with permanent black stains tattooed that looked like buckshot for over 30 years. Then the color faded to a light gray the last 15-20 years.
There was some neurological damage. When gripping tight water skiing, playing baseball, golf and such, the middle and ring finger would become paralyzed until the grip was released. I learned to live with it and adapt, what else could I do?