Help on Vinyl floors
If, by "a square" you mean that you have rigid vinyl tile flooring (that typically comes in 12"x12" squares) you can pull up and replace a single tile (or have that done, depending on your preference.)

If you have sheet-type vinyl flooring where one piece covers the whole floor, you either need to accept some new seams or replace the whole thing. 

Or put a rug over the damaged area ;-)