I tore my MCL last August and it was a pretty bad tear. I got side kicked through the knee at a karate tournament.
My knee felt real weird and unstable so I went to a doctor who said it was a sprain and i should get a full leg splint for 2 weeks then it should be fine. Worst diagnosis ever.
Got home that night about 6 hours after i hurt my knee and it the pain kicked in. Im suprised i didnt overdose on the amount of painkillers i took.
So i went to a physio the next day and he said it was Grade 2 possibly Grade 3 tear and it was borderline whether I should have surgery but could get through it without surgery.
Took me about 7-8 weeks to feel at least normal again and I lost 4 inches on my left quad from the splint and it looked real weirf with a normal right leg and a stick for my left.
My knee is the same if not better than it was before I did my knee in August so its doubtful that its permanent. If youre not sure if its a bad tear go see someone about it.