Baseboard time. I was going to strip this entire 14 foot section to the corner and replace it, but when I went to remove the short piece at the upper left, it starting pulling the base off the other wall so I left it. Thankfully, the previous installer cut an accurate lap joint so I was able to blend the new piece into it and not further disturb the corner.

Once it's all sanded and painted, you'll never see the "splice".