Index finger pain

Everytime i get on the mound, i do fine up til around 40-60 pitch when my index finger starts bruisin and bleeding right around the side where the nail touches the skin. I always cut my nails too, so what the freak is this and how do i prevent this from happening? Plz help cause this is really screwing over my pitching.

Which side of the index finger? Thumb side or middle finger side?

middle finger side normally

Hmmm… Maybe you cut the nail too short and it digs in?