Hardwood is a beautiful flooring surface, but when damaged it will require hardwood floor repair.
If the scratch barely penetrated the surface of the finish, you can repair the damage easily with a light application of a clear finish such as "Future" or "Jasco" using a cotton swab or small brush. Use the same finish that was applied to the hardwood originally if you can. In most cases, you will not need to restain the scratch, as the original stain usually penetrates to about 1/8 inch.
If you drop a heavy skillet or a hammer on your floor, and ended up with a rather deep ding in your hardwood, soak a sponge or heavy cloth in water until it's almost sopping wet and place it over the damaged area. Put a piece of plastic over the wet material and let it sit for at least 8 hours. Often, the wood will swell back up into place, leaving you with nothing more than a scratch to repair.
A more serious injury to the hardwood can result in the exposure of actual raw wood, maybe even some splinters. You have two options here:
1—Remove the damaged plank and replace it with a spare plank. This requires some skill and may be better left to a professional installer.
2—Fill the ding with a specialized wood putty, either colored to match your floor, or stainable. Sand it down to a flat surface after it has dried, and then finished with a clear coat.