I had a similar accident as a child.
Playing war in my neighbours’ garden, I was standing on a horizontal bit of wood on their tall fence, so I could see over it to shoot someone. It had been raining and my feet slipped off and I fell. It was only a few inches to the ground, but on the way down the underside of my upper arm caught on a nail.
Thankfully my neigbours’ mum was a nurse, so she took charge, ordered her son to fetch some of his comfort blankets to mop up the blood (thanks Ben), and, I assume, whisked me to hospital.
I remember being at the hospital, having the tetanus shots and stitches, but not much else.
Now I know that a lolly is the going rate for an underarm scar, I’ll have to make sure I was given one, or else I’ll be demanding payment, plus interest.