Pain in index finger, left hand

[Zabby76]

2 days ago I suddenly devoped pain in my left index finger at the knuckle. I can touch it and its ok, but if I move it at all in any direction, it hurts pretty bad. Late yesterday it started hurting some in the knuckle where my finger joins my hand,  top and bottom. Its sore feeling in that area when I touch it. A vein on the right side of the finger is bulging out some and it seems to be slightly swollen. I can bend it, it just hurts.