Okay, a few questions to clarify things a little more..
What substance did you IV?
Also, was there any rush? Or, if the drug doesn't produce a rush, did you notice a sudden onset once IVed?
When you removed the needle from your arm, was there any swelling around the area at that time?
I know you said there was no bruising or swelling but sometimes there can be a small amount of what looks like swelling near the injection site and it may fade after a few minutes or a few hours. I've had this for minor misses, I believe it's just fluid from the shot under my skin.
Stinging usually means you missed. If the stinging is really minor it could just be the substance you're IVing OR it could mean it was a partial miss. You could have mostly been in the vein but just partially out.
Here's the deal with the crook of your arm..... Or well, since I don't feel I have the qualifications to deliver this as fact, here is MY experience. When I first started IVing I used the vein in the crook of my right arm like most people. As I was inexperienced in IV drug use, I was only able to rotate between that spot and one other on my left arm at first. I was very careful but I'm sure I was essentially stabbing my arm with a needle those first few times, albeit gently stabbing.. But to hurry this along, for whatever reason I started to lose a little sensation in the area I was injecting. I would slowly put the point of the needle in, draw back plunger, and keep pressing forward till the small air bubble in the syringe was replaced by blood. I would depress the plunger and all would be good. HOWEVER.. a few times I must have slipped out after registering because a couple times I didn't get a significant rush and I felt the ever so slightest sting. And out of those couple times, one of the times the miss resulted in a big lump in my arm. It did not end up becoming an abscess, most likely because I was religious about putting hot packs on it (I'll go over that below).
A missed shot will usually absorb, just slower than if you got it into the vein. It's not like squirting it out onto the ground. So it could have kept you well. I would absolutely not use that same vein for IV for quite some time.. not worth getting an abcess if it's the same case as what happened to me. Are you able to hit other veins? Not sure of your level of competency with IV use.
What to do if you think you may have missed a shot: Immediately run the site of the injection under hot water. If there is swelling/fluid you can massage it gently to help your body absorb it quicker but avoid the exact injection spot as you don't want to irritate it or get bacteria into it. After 15-20 minutes examine the area.. if there's no swelling remaining, good. Keep a careful eye on it in the following days. If there's still swelling or if any comes back the following day, I would advise using hot compresses. Get a warm rag, fold it up, and put it under water as hot as you can take it. The key is frequency.. you want to do this 10+ times a day if the swelling is not going away. A nurse recommended using hot milk for the compress, though I think he learned it from his Mexican grandmother not medical school.. but hey, probably can't hurt. He also said I could rotate hot and cold for pain and to take advil.
IMPORTANT: If you get any of the following symptoms: redness/inflammation or pain at injection site, fever, or any signs of abscess (egg shaped lump which may or may not be soft at the tip of the "head" depending on the stage) you need to get medical attention immediately so they can give you antibiotics and lance the abscess if needed.
Edit: and of course Tri and CH post while I'm taking days on my post. Might as well delete mine

Yeah, asked WHAT he was IVing cause in Social he mentioned IV bupe... not good!