As soon as the abrasives come out there's a 50/50 chance you'll end up in complete refinish job. Wait till after the season to do that.

If it's not too deep think about this interim job that'll help a bit and protect the area.
Steam the scratch (won't help much but will lift up what wood fibers that can be lifted) and let it dry out. Then finish the scratch carefully with a little Tru-Oil using a toothpick.

I use a soldering iron pressed onto a damp towel to push the steam into the dented area.