I was injecting this morning and all was well (aspirated, went deep enough, etc.), but when I pulled the needle out a stream of blood followed. After a couple of minutes it subsided and I didn't think too much of it. Now, a few hours later, there is a big painful lump where I injected and it's beginning to look like a bruise. Is this just the joy of nicking a blood vessel? Nothing I should be concerned about is there?