injured while jump roping?

by Alexander Zapata
(Iraq)

Today, I was jump roping as a form of cardio and I came down on one foot and I guess I landed wrong or something, because my knee kind of popped, and I felt a shooting pain from my knee down to my toes.

Ever since then It hurts whenever I do anything, move my leg or go up stairs. I can walk, but only with a somewhat painful limp.

Can I still work out with weights, if only upper body? Or should I wait and let my knee heal before attempting any sort of exercise?