Where to buy wood stain pens?

Currently staying in a long term airbnb while Im studying abroad for a semester and I already royally fucked up…

I do my own nails and spilt a small amount of acetone on the dining table and it very noticeably removed some of the varnish on the wood.

I’m trying to not freak out, but where can I easily buy those like wood varnish pens for touch ups? It’s not a huge spot so I figure it can easily be patched up but damn do I feel awful about it. I can speak some conversational japanese, and I don’t see any issue with talking to store staff if needed— I just don’t really know the best place to buy these things yet.