[idlafie]

Your answer's simple. Take the tire off & remove the screws holding the plastic fender liner in place. Once the screws are out, remove the plastic fender liner. Removing the plastic fender liner will give you access to the inside part of the fender. Use a pry bar to push the damaged fender portion out of the way & then use a Bolt-Out screw extractor kit to remove your stuck screw.
Hope this helps...
ID