stripped bolt in bed rail

I was installing my new bed cover last night and had to take the bed rails off. Every thing was going fine until I got to the last bolt nearest the cab. It's ridiculously tight. Anyways, I got my 4mm allen wrench and started to remove it, but it wouldn't budge and I eventually stripped the bolt head. I bought an extractor from the store and tried to drill it, but it's a hardened bolt and it broke my drill bit. I'm going to try to dremel a slot in it for a flat head screwdriver and hope that works. But for now, I'd say I'm up a creek. Toyota torqued the hell out of this thing.

 

VICE GRIPS... they always work when in a pinch...

(I actaullt did the same thing putting one back in with my Dewalt drill I guess i was off a bit so a stripped the head before it was all the way in...)
I might get out the vice grips just so i can replace it.

 

Mine are torx style not allen style. Tried one of those yet?

 

Whoops, meant torx, the bolt bed cover bolt that replaces it is a hex.

Got it out with a dremel, screwdriver, and some pliers. All is right with the world. Well, at least in my garage.