I agree with Knotted - it might really hurt to put on a neoprene sleeve on your knee. I have in the past more than once banged my knee really hard riding mountain bikes. All times, it was just a bruise which hurt like h*@l but really was nothing more. I sure would not have wanted to put anything tight around it. Sometimes, I can remember it hurt to just try to wear tights!
I vote for ice and more ice - oh, and of course time for healing, but you will probably be fine to ride. Just watch that it doesn't start to really swell.