Dents and gouges are both flaws in the wood. But they are not the same thing, so they should be repaired differently.
Dents are compressed wood. The wood fibers are still intact, just pressed down or indented. Gouges are also indentations, but the wood fibers have been torn and usually some of the wood has been removed.
Dents can usually be steamed level. Gouges have to be filled with wood putty or some other filling material. Sometimes the indentation is not clearly a dent or gouge, so you can try steaming before resorting to filling.
To steam out a dent, drip some water into the depression using an eyedropper or syringe. If the dent is shallow, the water may swell the wood enough to bring it level with the rest of the surface. If the water doesn’t work, drip some more water into the dent and cover the surface with a dry cloth. Then apply a medium hot iron to the cloth. The hot iron causes the water to turn to steam, which enters the wood and swells it. You can do this several times.
Whether using water or steam, sand the wood well after the moisture has dried out to eliminate any raised grain.
Because water raises the grain of wood, it’s best not to lay a wet cloth on a wide area of the wood, as is often recommended, before heating with the iron, because this will increase the amount of sanding necessary. It’s best to keep the wetted area as small as possible.