Black nail cuticle after injury?

hey guys/girls..i just had an accident almost a month ago and had to get stitches on my right hand index finger just a little above the bottom part of the nail or cuticle(i don't know exactly what they call it)...anyways the stitches are removed but after a few days of removal, the cuticle skin just separated from the nail and now, almost a month after the accident, the nail looks a bit black/grey just beneath the cuticle skin but only on the right side of the nail where the injury happened...and even my nail feels weak..am i gonna lose my nail? is this permanent? what do i do..i am scared..will it heal? any medications? pls help..