I was in the same boat for SO long...
Trying to slam bupe into the last 1.5 inches of inflamed, pink, punctured veins in each forearm. Now, I can't imagine what I was thinking -- I never got a rush or any noticeable effect at alll. Just fixated on the needle, I s'pose. Kept it up for months, veins never been the same. That was years ago.
I'm just cuious - Why are banging your subs? Are you on maintenance/a prescripton & trying to save dough? Or do you buy 'em off somebody just to get high? Seeing as you're 'bout outta veins, I'm thinking you must do it pretty often if. Do subs still actually get you high?
Don't skinpop the pills man! I know, sounds like an accident^ but jeez, that's a shitlotta matter to be depositin' unda' the skin.
Finding veins, hmmm.... There's all the things like tying off, putting a warm towel on the area (wet washcloth, microwaved to hotness + Ziplock = hot compress - the mess), doing pullups or pushups right before, mas ejercicio, and so on, all that good shit...
Neck is a bad idea. Ever notice how bad your hand feels after a bad shot (that swollen tingly numb itchy blotchy pain with raging hives, like you put your hand in a bee hive)? What if that happens to your face or brain?? Or just yer eyeballs? I've never actually heard of one popping out or anything from nicking an artery on a missed neckshot, but there's a whole lotta ugly things that can happen when neck shots go bad.
Really, my best advice boils down to just one word: squirtitupyourassholeintoyourrectum.
EDIT: AKA "plugging," see next.