What Causes A Persistent Brown Spot On Finger After An Injury?

At my job about 2 and a half years ago I was trying to get 5 cases of peaches while accidentally puncturing my right hand finger closet to the pinky exactly at the top line on the side finger with a staple. All I did was wash it put a band aid then kept working. To this day there's been a brown spot on that same spot of the finger. It healed with a brown spot in it. To this day there's some pain in it. And most recently I pushing my friends sunroof (it got stuck)and at that very same spot all of a sudden I felt pain in the finger. I looked at it and it was red. Later on I felt some pain on my finger when I looked there was another brown spot about half an inch above my original brown spot funny thing though it connected like a snake but it isn't an open cut. Is this serious condition and should I be worried that one day it may get amputated?