you might of hit a major blood vessel i hit one in my arm when i tried to cut my arm off with a hedge trimmer It would not stop ended up with a tea towel and gaffer tape bandage and drove to the hospital where they routed around trying to find it and they then clamped it and sewed it up I wouldn't of minded but i had no aesthetic and had to hold the clamp for them as they sewed it I did get a cup of tea out of them after through
My friends wince every time I say I'm working on the camper expecting another injury. Glad I'm not the only one. Hold you arm up for about half hour that should stop the bleeding. Make sure you have under arm deodorant though! How you feel better soon dude.