I Injected A Small Amount Of Meth Into What I

I injected a small amount of meth into what I thought was a vein on my right arm. The blood did not look pinkish like arteries usually do but instantly my hand started to swell. I have injected heroin into an artery before and it was similar although my entire arm swelled immensely (worse than this) and it was very red and painful. There is not much pain going on here and it's only my hand that is swollen. It's only been about 10 minutes and I'm feeling a small amount of relief but it's still numb and swollen. What could have happened?