Screwdriver bit, there are lots of them. JIS (Japanese Industry Standard) screwdriver bits are different from Phillips. They have a shallower angle on their blades, and while a Phillips bit will "fit," it won't seat all the way down into the screw head. When higher torque is required to tighten or loosen the screw, a Phillips screwdriver will strip a JIS screw, and vice versa.

As others have mentioned, carefully drill it out with a teeny tiny drill bit, maybe make use of a teeny tiny easy-out. Replace with a slightly larger screw or just leave it empty.