I read somewhere that Apple uses Loctite on their pentalobe screws. I researched what would melt Loctite and the answer was HEAT. So I carefully heated the pentalobe screws with the nozzle of a glue gun (without the glue, of course), and after a couple of minutes, we could screw the screws right out.
This answer is for unscrewing pentalobe screws in general. For the guy with the screw with the stripped head, heat the screw and then use a pentalobe screwdriver (TS4 1.2mm or 1.4 mm) or a #00 or #000 phillips screwdriver to remove it.
Hope this helps.