If you used a screwdriver to turn the lock cylinder/ignition switch, irreparable damage may have occurred to the lock cylnder (where the ignition key fits into) as the lock cylinder has a magnet that passes under GMS Passlock sensor as part of the antitheft system. This problem may be complicated insofar as restoring/repairing security or bypassing it entirely (provided it can be done with a damaged sensor. Here's background info for you or someone familiar with GM security systems; https://www.tradecraftspecialties.com/Passlock2