I have a small, fingernail size bump on my neck that may run along a vein, but if so, the vein is too faint to say for sure.
I use cocaine 1 - 2 times a month - as much as 4 -6 grams at a time (a "bender"). Otherwise I lead a healthy lifestyle ~ no smoking, not much drinking, and I exercise rigorously 5 -6 times a week.
I am associating the bump with my cocaine use simply out of fear and because it's the only abusive activity in my life.