It's pretty tricky, because you need to match the finish of the counter. That's why a professional is your best choice. If you want to do it yourself, then pick up some clear two-part epoxy or some clear resin patch. Apply a small amount of the product to the damaged areas, making certain not to overwhelm the area. Start with just a little and add more as necessary to completely fill the scratch. The product is self-leveling and will only need time to dry before you can perform the final step to this repair. Once dry, lightly sand the area with 400 or 600-grit wet sandpaper. Or you can use a little rubbing or polishing compound to achieve the same effect. Give the entire top a good waxing with an auto polish or paste wax. It probably won't be a perfect match, but it's better than having to replace it!