I feel your pain... I've been an IV user for the better part of 5 years sometimes using 6-10 times a day... I use fent and meth (which is corrosive and definitely isn't good for veins but oh well) my arm veins became totally unusable last year, I was able to use the veins in the waist area on the left and right sides for maybe a month or two before they became unusable, since then I've been using my hands which for some reason seem to be more resilient than in other places, but they have pretty much all collapsed now even with only using for a few weeks over the last year, zero veins have recovered, most recently I have been using the veins on my feet but they seem to not last very long... Its a really shitty feeling having dope and being super dope sick and not being able to get a vein for hours..yet I still would rather go through the hassle than smoke the dope, once you have became a major IV user smoking heroin is honestly pointless, like to the point where I have turned down many many times people offering me a free dragon because frankly it's a waste of dope.