I was also hitting my nose a couple of weeks ago. I didn't know what it was until I looked at my string nock and it had blood on it! I tried a serving nock and it didn't work either(although I did put super glue on it which made it as hard and rough as the metal one so no wonder it didn't work, DUH!).
So, with some help on here, I was able to figure out what the problem was. I was trying to increase my draw length and this was causing me to hit my nose every time. After we figured that out, I went outside to shoot and I went back to my old anchor point and never hit my nose again.