We had our floors professionally sanded and polyurethaned with 4 coats
of oil-based polyurethane a few months back.

Since then, we have made several scrapes and even gouges through the
layers of polyurethane and into the wood.

Is there any way to "patch" these scrapes and gouges without having to
resand and repolyurethane the entire room? (It doesn't have to be
perfect, just better than raw wood scrapes).

What is the best technique?