OP-- Here's some stuff for the now and future (should you, for whatever reason, go back to the needle.) To put this out there, I am a mortuary science student so do have experience with para-surgical technique, and thus some pathology/ microbiolgy training. (And used to work in chemical dependency counseling) so do know a little bit about medical stuff. That being said, I am no doctor, so if in doubt about any info that you see on here, DEFINITELY seek medical care from a trained professional.
To start: You say you don't know if you hit a vein. As Korn3X stated, the burning or stinging that you felt upon "injecting" very well could have been because you didn't actually hit the vein, or poked through it or something to that effect. I have never injected roxies, but have injected a fair share of dilaudid, heroin, morphine, ketamine, and benadryl and never experienced ANY sort of discomfort after pushing in the plunger EXCEPT when I missed a vein, punctured a vein, or put the drug into a muscle. That being said, irritation from the substance under the skin can definitely cause some irritation on its own (redness, rashes, bruising, etc.).
You also mentioned that your VEIN had some hardening in it. If the vein has hardening not only around the site(s) of injection, but instead alongside the length of the vein for a couple inches or more: well, this may mean that you DID hit the vein, at least in part, and that there is some scarring in the lining of the vein's tissue. This is likened to VERY mild necrosis of the veins. This happens frequently with some regular IV-drug users, but shouldn't develop THAT quick in someone only beginning to use drugs intravenously. (Not to say that its impossible though.) HOWEVER, if the substance that you were using is higly corrosive or irritating to your personal physiology for whatever reason, yeah, it could cause instant necrosis. (Necrosis of the vein, BTW, is in part of what causes the "track marks" users get.)
Given that you do have hardening of the vein(s), it might be fair to say that the roxi's weren't filtered properly, or that the pill itself contains something irritating) and has caused almost like an allergic reaction. Also, after seeing the photos of the injection site, the NUMBER or small reddish bumps leads me to believe that you at the very least had some sort of (partial) reaction to the needle, the drug, or whatever else was pushed in your skin. Try a topical benadryl (diphenhydramine) and see if that reduces any of the redness or itching. If it does significantly, its fair to say you just had a reaction.
If ANY of these things begin to happen, though, it may be fair to say that you do have an infection (e.g. an abscess, staph, or other bacterial infection) and in that case you should DEFINITIVELY go see a doctor as this can become life-threatening:
The injection site, vein, or surroundingareas becomes swollen, very red, hot or warm to the touch, painful, and these symptoms get WORSE during a 12 or 24 hour period. The "bumps become more raised, pronounced, and larger in size instead of gradually going down or remaining the same. You experience a fever, chills, or shaking. Severe nausea/ vomiting. The appearance of a large bump or abscess in another part of the body, even if it is not in the area that you shot up in. The "clear" liquid you see when sqeezing the bumps starts looking thick, yellow or white or green, and more blood-filled.
For the time being though if your symptoms aren't scary, things you can do to treat this as are: Gently wash the area with anti-bacterial soap (the orange stuff!) and couple times a day, take benadryl or use the creams if this helps, and if you are STILL unsure and have access to it, take a cycle or a BROAD SPECTRUM ONLY antibiotic, but I don't recommend doing this unless you really fell like you need to as you can build a resistance (similar to an immunity)immunity to certain antibiotics and future treatments may become useless, even to dangerous bacteria! Some BROAD SPECTRUM antibiotics include amoxicillin, keflex (or cephalexin) and penicillin. Be aware that many people experience allergies to antibiotics, primarily penicillin, and also be aware of potential side effects. For instance, drinking booze on top on antibiotics is often a disaster for terrible gastrointestinal stress.
The MOST important thing for now is to remember that SAFE-SHOOTING practices are very important, and it is also very easy to come across info on how to properly inject drugs. There is a lot of info on the harm-reduction site
www.heroinhelper.com and you can find lots of info on Captain.Heroin here on bluelight.ru as well. Here are some of my favorite links:
http://www.heroinhelper.com/curious/chemistry/internet_pills.shtml (Has specific instructions depending on what drug/ pill you are shooting.)
http://www.heroinhelper.com/user/admin/where.shtml (A quick guide that lists the pros and cons of shooting in varying areas of the body.)
Hope you're doing better!