[Jamie]

I don't think you can make it worse. It all depends on what you can live with. No matter what you do, the repair will be somewhat visible. I sent some veneer, but it may be darker than you need. I like codefox's idea. The method I have used is to take a piece of paper and a pencil and make an etching, then cut veneer to fit. Fill in the area as best as I can with some veneer, trying to match the missing places. Glue it in. If it's not level, I lightly sand the new veneer. Then I smear some Timber Mate colored wood filler over it and wipe off the excess. After that, I spray some toner or clear lacquer over the spot.

Timber Mate is a product now being carried by Woodcraft stores. It's imported from Australia and guys who lay wood floors use a lot of it. It's water soluble, comes in a bunch of different colors and works better than any wood filler I've ever used. You can thin it with water, and if you mess up, a wet rag will allow you to start over.

If you don't feel comfortable doing it, call a pro.