Tashia, hon....please try not to worry about your knees. One step at a time here. Your tooth could very well be the cause of you feeling so bad. These things take a toll on your body. Try to get as much rest as you can. Once you get the dental problems under control, lets see how your knees feel. In the meantime, do whatever it takes to make yourself comfortable.
I do think it's a good idea to make an appointment with your OS just to ease your mind. You can always cancel it if you start feeling better.
The numbness and stinging are both normal. As you guessed the stinging is most likely nerves activating...that can go on for quite a long time. The numbness may or may not go away entirely. You must give it time as well.
What is it with your tooth that's causing so much difficulty? I really feel for you.....