I shot myself when I was about 15 with a .22. Was out plinking in the woods and shot the underside of a fridge. Whatever that big chunk of steel was underneath, it caused the bullet to riccochet directly back and hit my index finger as I held the front stock. Missed my eye by about 2" I'd guesstimate.
Pain level ?? Maybe a 4. It hurt less than getting my knuckles crushed in a door frame as my sister tried to close her door as I gripped the doorframe to help a friend carry a large chair down the steps.
BTW, this is the last thread I would have ever imagined posting in, but I pretty much forgot about it until giving it some thought.