The syringe and water works great for bringing out dents after the covering is already on the plane. Get a small syringe and fill it with water, then inject water into the dent and then heat them your covering iron. The heat will turn the water to steam which will expand and push out the dent in the wood.

This is great for getting small dents out, but it does had limitations. Larger dents or breakages will still have to have the covering pulled off and repaired.

Ken