Okay, I tried giving him a treat, and he gobbled it right up. He also stood on his back legs begging for it, so I'm fairly sure it's not one of the back legs that's hurting him. I did notice when I made him sit that he lifted his front left paw for a couple seconds, so that's probably the one. Again, I tried pressing on it in various places, and moving it around a little bit, and he didn't whine or anything. But he's still limping just as badly. I'm freaking out.
