I hope i didn't destroy my lower - ATI Outdoors AR-15/AR-10 Pistol Grip Screw w/ Star Lock Washer

Swapped out the trigger in my AR lower. The pistol grip was a basic A2, which was fine but my lower parts kit included a Magpul grip. Something told me to just use the screw and washer that was on it but I used to Magpul screw and it was a mistake. It stripped the screw hole I cannot get the thing to tighten up the grip. I will NEVER use that big screw again. Screw and star wash lock for life.