I know this isn't rocket science and admittedly, I'm not the handiest of wrenches.
My original mirror was mounted with just three screws but the mirror itself was loose as all hell. I broke the screw trying to retighten it.
So I got an aftermarket LMC one and tightened it, only to have the three screws that are supposed to hold the mount in place not grab into anything.
So I know of no way to get a nut back there or any trick to use short of using some kind of super glue and hoping it holds.
Right now, I've gotten really good at only using my side mirror.
Any ideas?