Thanks for posting your query.
From description it seems to be soft tissue injury
over your left knee and leg. It generally takes 10 -15 days to heal.
If pain persist beyond this ,I suggest you to consult an orthopaedician nearby for a detailed examination. You may get the X-ray of the area affected under his/her guidance.
Meanwhile you can take anti-inflammatory drug like motrin
to reduce pain and inflammation. Avoid putting full weight and rest well.
Dr Saurabh Gupta