What Causes Numbness And Tingling In Finger After An Injury?

I shut my right index finger in a car door, I iced it and put a splint on it . It has been about 31/2 weeks and the tip on my finger is numb and tingling ,and the nail is a little black under the nail bed but not a lot,but I m worried about the numbness should I go and get it checked even though it s been this long was told that they really can t do much for a broken finger.