Hello, your not the first and definitely wont be the last screw, screw up. : )
I would first try tapping very gently a straight bladed screw driver into the old hex hole , with a thin blade just a bit wider than your stripped hex. Until you get a good bite to start removing the screw. You will have more torque force with a straight blade then with the hex and may also loosen the screw by the tapping action.
By chance that doesn't work for you , you can try to get a bite of the outside screw head with a pair of small duck bill or flat nose mini pliers with teeth. Or a pair of the ifixit screw extracting pliers.Screw Extracting Pliers
I would go nose down onto board(its only contact with a ground plain) squeeze screw head and turn.
Only if all else fails would i think of drilling or cutting out.
Hope this helps and good luck.