Hi, Chris. There are a couple of things that you can try. On dents, take a damp rag and put it on the dented area then hold a steam iron on it so that you direct the steam into the wood. This may bring the cells of the wood back into shape.
Minwax makes a pen, like a magic marker, that will cover the scratches. Wipe it on and blend it into the wood with your finger.
There are some good books on this subject that can give you more tips but these are safe and work. Just about any filler, with the exception of Minwax's colored wax type filler, will require some difficult refinishing. The Minwax filler comes in small jars and is only good for very small depressions.