Climbing with my usual partner - I was belaying on a lead climb. My partner had just placed the first piece of gear and was <1m off the ground. I stepped in towards him to point out a foothold, as he stepped up and I stepped back, I caught the tip of his nut key, which was on the back of his harness on the inside of my nostril! This caused a small wound and considerable amount of pain. I lowered/dropped my partner to the ground (this is a debatable point). First aid was self administered.