it means "injury of vein ; venous injury".

作毒品人的血脉。听起来像歌词，是吗？

It's a slang term used to describe the veins of people addicted to hard drugs (specifically drugs that require injections into the bloodstream). These people, for a variety of reasons, will have bulging veins that are usually accompanied with some bruising near the elbows or ankles (common injection sites for an addict). People with chronic hard drug addictions are called "junkies", and therefore, their iconic bulging veins are called "junkie veins". Other people who simply have entirely separate medical conditions may appear to have junkie veins, so you don't necessarily use that phrase ONLY to refer to drug addicts. Of course, you don't normally use that phrase at all. It's pretty insulting to say that to someone who's not an addict, and it's arrogant to say it to someone who is. You'd only say something like that if you're trying to hurt a person's feelings.