Not as bad as me the other day, putting the plugs back in my 99 mustang, and one of them stripped out the threads. No matter what I did, the plug wouldn't tighten, and I thought it was right, it seemed like it was perfect. Well worse came to worse, I mixed up some JB weld, put it around the threads on the plug, and cranked her in there. Worked like a charm. No problems (yet)
Anyways, soak that pup with some PB Blaster, then using a small drill bit, start drilling (if you have room), go down a few MM's, and keep making a straight line, till you have a slot... then use a big flat blade screw driver, with a big thick handle. Drill a hole through the center of the screw driver, and use another screw driver as a T-handle, stick her in, and see what you can do.