quad strain WHAT IS THE GRADE?

by Teresa
( Tx, USA)

How do you know what grade your quad strain is? I have swelling on the outside and on the whole center of my thigh. When I strained my quad muscle it felt like burning and tearing when it happen, but of course I tried playing though the pain. By the last ending OF kickball I couldn't walk. I almost fell to the ground,I had no strength in my leg. It has been 3 days now and still swollen, but less pain. No discoloration. Also when do you know when to start stretching out you quad muscles again? Thanks!