my middle finger is pain extremely swollen and throbbing like crazy

the tip of my finger felt really bruised for 3 days then the next morning I woke up and it extremely swollen i can feel my pulse in my middle finger very strong. I shined a light threw my finger and for the most part it was clear and so were the other fingers but on that particular finger I seen a dark spot in it and you could see the pulse it is extremely painful its feels as if someone is trying to work my finger now on or explode my finger