how do i get an ink stain off a rubber floor?

not sure...try rubbing alcohol or nail polish remover
Use hair spray. The kind in the pump type container. Cheaper brands work best. It's the alcohol. Rubbing alcohol will work, too, but the hairspray is easier. Only spray or dab small quantities at a time. Use a terry cloth towel-preferrably white, to "blot" at the stain. It may take several attempts to get this stain up, but it has always worked for me. Let me know how it works.
you cant
Not a hopeful situation. Best stain the whole floor that new color.