and for the best results you'll probably want to hire a carpet installer to repair it (going rate in Ontario is approx.$75-$100 cdn). However if you want to tackle it yourself, you will need a carpet 'cookie' cutter, this looks like a round cookie cutter about 5" in diameter, but has very sharp serrated blades on the underside of it. The process involves rotataing the carpet cutter over the affected area, applying carpet seam tape (cold type) to the underside of the existing area, with the sticky side up, then cutting a repair patch from spare carpet, or from inside a closet or other hidden area, and putting this patch in the opening, where the damaged piece came from. Make sure that you make sure the pile direction of the repair runs in the same direction as the existing. Hopefully this long-winded explanation helps. Have fun!