Originally Posted by Retro Grouch
Well, you can always replace the crank later if you need to. If it was my bike I think that I'd try the cheapest solution first. I'd run a pedal tap through from the back side to clean up whatever thread is left and see how it goes.
Pretty much what I did when the exact same thing happened on a friends bike. But I instead of a tap I just used the pedal. Screwed it in on the back inside of the crank all the way in to clean out the outer threads then put the pedal in the correct side. Never had a problem since.