Your knee is probably fine now. With sprains, I usually go with the RICE method. It's not exactly traditional as it is modern medicine that you learn if you ever go see a doctor. RICE is an acronym for:
Rest
Ice
Compress
Elevate
The rest is for obvious reasons. Your joint, your knee in this instance, is injured. If you keep using it, you'll only make it worse.
The Ice is to reduce swelling. Be sure not to over-ice your joint as this can cause more harm than good. Generally what I've found in my own experience is to ice it for about 10-15 minutes and make sure that the ice or ice pack isn't directly against your skin. Put a paper towel or something inbetween.
Compressing the joint is basically just wrapping it up to ensure the joint stays in place and also to give you support.
Elevate is kind of the same idea as the ice in that the idea is to reduce swelling. Swelling is caused by increased blood flow in the affected area. Elevating the injured limb above your heart will help the blood from, uh causing swelling. And when I mean above your heart, for an injured knee you'll want to lay down and prop your leg up at the knee with a pillow or a few pillows.
I hope this helps if there's a next time.
Now, what I want to know is how do you fix a torn meniscus without surgery? I tried to rehab my knee, but it's been 6 months since my injury and I still feel pain when I bend my knee all the way.