Last week I was working with a roll of metal lath(metal cage for holding stucco on a wall). I was cutting it so the ends were razor sharp. It comes in a roll and while trying to flatten it out, I let one end go and it landed perfectly on the big vein on the top of my arm. It spurted twice, then stopped. Then I watched the area of the puncture grow to the size of half a golfball. I kept an eye on it throughout the day and the swelling went down. The area felt bruised for the rest of the day but by the next day it was like it never happened.
Now it is a week later and the opposite side of my arm has a really big red bruise. Actually looks like the underside of a dead person when the blood settles which is kind of scaring me. I am afraid the blood is still in me. Is this bad?

It sounds like blood went to the other side of your arm. (Yes, lividity in corpses is blood settled to the bottom of the body where it was lying at the time.) But it doesn't mean anything awful in your case, probably. 'Blood inside you' is just the definition of any bruise. Your lymphocytes and so on will break it up and carry it away in the blood in a few weeks or so.