What Causes Black Discoloration On Fingers After Stitches?

Ok I had stitches put in last monday my finger has continued to swell I went back to the er 3 days ago they just said that it was sprung put it in a splint told me to take motrin for swelling and percocet 5 for pain the whole tip end of my finger is black and my knuckle is black I can not bend my finger what should i do? what could be wrong with it? I was suppose to have the stitches taken out today I plan on going to a different hospital tomorrow morning I had a rn to look at it and the stitches are stuck in the cut please help