Stuff happens, even when you are careful. I was remodeling a kitchen and accidentally dropped a can of glue that spattered and instantly solidified on the floor. The floor had recently been sanded and stained, making my mistake even worse. My flooring guy came to the rescue and was able to do a modified refinish. See the photos below for details.

Here you can see what one second of error can cause.
My floor guy is taping off the edges of the boards.
Using a scraping tool to remove the glue.
The area to be repair was hand sanded to only remove the top layer, leaving the stain intact.
A new top coat is applied and the floor is as good as new.