Ouch! My Nail!

Hurt my forth right finger on a bus. I also don't know what happened, but when I went up the stairs of that SBS bus, my right hand brushed against the wall and the next thing I felt was a bearable pain on my finger. I took a look when I sat down, and realised that a part of the nail had chipped off! Now there's a wound on that finger, and I am having some difficulty using my hand…