Gouges depend a lot. You can try it - it won't hurt (assuming you don't burn the wood/finish, which is often pretty hard to do).

Dents usually just have bent fibers. They are pressed in half or whatever, but still together.

Steaming works because it straightens the fiber back up into the original shape. They want to be in their original shape.

Gouges usually have ripped fibers on the edge. Steaming will not work because it does not put the fibers back together :)

Now, it's never quite this distinct. Even gouges are usually a mix of bent/dented fibers, and ripped fibers.

So steaming is worth a shot, and can often make it better depending on how much was a dent vs a rip. Just don't expect miracles. Especially, if it's visibly torn. You can often see whether the fibers are ripped with the naked eye.

(and if your eyesight sucks, a 20x loupe from cvs or whatever will definitely show you)