What Is The Treatment For Pain In The Knee And Leg?

I was playing soccer and I kicked the ball with the outside of my foot, I felt some a weird feeling at the inside of my foot, i played for the next week which was stupid. Then it got to the point where i couldn't not. Now when I extend it and push on my knee cap it hurts, i can run and its fine but when i plant sometimes. Its kind of a sharp pain toward the bottom left of the knee. I haven't done anything in 3-4 weeks and i don't see that much improvment in it, what can i do to make it better/ what could i have done?