You can recover your veins but it will take much time and effort. They won't come back by themselves. I used to have a pretty nasty IV habit a few years ago and just recently I seen the veins in my elbow crooks poking back out. How did I accomplish this? Alot of working out. Lifting + cardio. And I mean ALOT. The more cardio you do the harder your heart works to pump blood through these veins and eventually your veins will adapt and grow bigger and come out of the muscle where they have receded. This took me years but honestly a couple years to see my veins come back is relatively short time to see these results. Most IV users never see their veins again!