It's just the top spraypainted, right? Cause if he purpled up the base, you might as well throw it out. Paint on the top won't matter that much, just look stupid, and it sounds like the board would anyway.
If you reaaally want it off I guess you don't have much choice other than to lightly wipe it with paint thinner and scrape it carefully. If he spraypainted it I doubt he waxed it either, one more beating shouldn't matter.