I have always had a small bottle of Revlon clear nail polish for such occasions; I would clean the surface with alcohol, and apply the polish. Never failed me.
You can get a small thing of touch up paint from the dealership or you can order it from Amazon. That’s what my husband did for my fusion. I put on my tailgate assist and with a lot of luck I didn’t scrape it. I do love the assist, the husband gave it to me for Christmas.