Hydrogen peroxide from beauty supply store https://www.youtube.com/watch?v=nh_TZWWK9fs
You'll end up having to refinish at least that area.
You can also try baking soda made into a paste with vinegar. I've been using baking soda and vinegar for a lot of my cleaning and it really does a great job. Here's an article that explains it plus a couple of other ideas. Wishing you the best.