Don't ride it off at all. If the pain feels like it's behind the kneecap it's usually your cleats that need to be adjusted (i'm assuming you're riding with clipless pedals). Saddle height also should be checked.
The cleat should put the ball of your foot directly over the pedal axle when your foot is level and not tilted forwards.
__________________
Originally Posted by
jsharr
A girl once asked me to give her twelve inches and make it hurt. I had to make love to her 3 times and then punch her in the nose.