I never had any problems slamming heroin, always used the same four veins and they never gave me any trouble for all three years. Then I switched to meth, and my veins immediately started giving me a hard time. After a long while of having to really work everytime I used, out of the blue one day NO vein would work for me. I refused to give up. I was trying for 30 min at a time, take a quick break to chug a bottle of water, then go right back to it. By the end of it, my friend said I was sitting there trying for 8 hours(no joke), I had went trough crying hysterically, screaming, begging, wishing to die, and pleading to my veins like they were some serial killer to just work one more time, I had smashed everything in sight and punched multiple walls, had blood ALL over me and everywhere I was sitting because after so long I got too frustrated to even clean it up and didnt even care, I had searched every way to word what I was going through and how to fix it on google, and read every blog I thought could help at all. I had a needle of probably only blood. and about two riggs worth of a blood, water, and meth mixture in my cooker, and still wouldn't stop. The only reason finally did was because my friend(who had left for work and came back to me n the same spot STILL trying) grabbed everything from me in tears and everything got spilled and broken in the worst physical fight I've ever been in(due to me attacking him because I was really going to kill him for stopping me). I laid down on the floor and begged him to just kill me already, and I guess cried myself to sleep eventually.
Literally, the next day we got caught up with shit and I went to jail for a month or two. So I never got to try again. It probably saved my life honestly/:
When I got out I went straight back to it tho, but my veins were a little healed by then and I went back to only having a hard time. I dread the day that happens again. And that is why I urge anyone who has never used a needle not to even try it, you could very well end up like that, and from other posts I've come across, that's not too uncommon.