I would really chalk this up to your personal risk assesment. I wouldn't make a habit of it but a mild painkiller for a short time should not be a big deal, people do much worse. But if the swelling persists, gets worse, or you start having addition complications from the injection you should...
This is somewhat of a relative question, it depends on why and who is looking for it. As far as actually actively working in your body probably just a few days. If you need to pass a blood test then I would wait 2-3 weeks
If you don't want to be a daddy keep wrapping it. Don't put your future into someone else's hands if that is not what you want. The pill when taken correctly is over 99% effective but somehow I know several fathers that swore their girls were on the pill but their is living proof they were not...
It is pure jealousy and only perpetuated by those that are not doing well with the ladies or with the bank account. I also notice a huge difference in the reaction I get when I am out driving alone vs when my girl is in the car as well. I guess it ruins their penis argument when they see who I'm...