What Causes Painful Knot After Getting A Meth Shot?

Hi, my friend almost 2 weeks ago was shooting me up with crystal meth, almost 2 weeks later and I still have a painful knot where he completely missed. Then in my other arm he punctured my vein and has caused a light bruise that is still there. The vein that got punctured is also swollen lightly. What do I do to remove some of this pain and get the knot to go away?