but it shouldn't be much of an issue.
make sure everything is off, disconnected from power, and you are grounded.
you could try gripping the edges of the screw with a pair of pliers, needle-nose probably the easiest;
either turn the screw with the pliers themselves
or lift with the pliers while the screw is being turned with a screwdriver.
or try using a very thin flat-head screwdriver;
wedge the flat-head under the screw's head a bit and lift screw from the motherboard as you are unscrewing with another screwdriver.