Sorry, knee, no more hanging

I guess I probably strained a ligament, or did something minor to my outer meniscus, though the internet is fucking useless regarding knee pain: no I don't have arthritis. On Sunday I hung briefly from my left knee, with it over a bar and the foot hooked under an orthogonal bar, as I did many times when I was 12 with no ill effects, and now it hurts behind the knee when I actively pull the heel toward my butt using my hamstring. (Or when I passively close the knee tightly as for butterfly stretch, but it does go further without pain when the motion is passive.)

There's no reason to think it won't get better. Every reason to think I'm not interested in aerials, though, if I now can't hang safely from EITHER knee. The left one was always the one I was okay hanging from! Le sigh.

It only now strikes me that this, the left knee, is the one I've been feeling the back of when doing pancake stretching lately. So maybe this isn't completely a sudden onset? Hmm, it is, though. This new thing is more on the outer side, and the pancake feeling was more on the medial side.

Treatment plan: the usual ibuprofen, moderate motion and sleep.