Deborah, it would be really nice and convenient if you had some of the same paper from the original installation you could patch with, but I'm guessing that you don't.
Depending on the pattern and your stick-to-itiveness it might be possible to re-create repair material, but I think it's very unlikely you'd get satisfactory results.
Perhaps you might "borrow" the paper from a covered or separate area, such as a closet or behind the refrigerator? If you can find an area like this, and the paper is fairly sturdy, you can with luck and great care remove what you need for a repair.
Beyond this, I'd say if the damage is all below, say, 30 to 36", you might consider doing a wainscot of a complimentary paper, putting wood trim or a border at the top edge. Hope this gives you some help or alternatives!