GAZOO
Pre-takeoff checklist
Discovered i left my mag switch turned on over night. Is this bad?

It's a bad habit to get into (forgetting things)
Agreed......
Learn from this mistake Gazoo ...
Agreed......
Learn from this mistake Gazoo ...
Just wanted to make sure i didnt really mess anything up or burn out the mags some how
With the engine not turning (You did remember to stop it before you left, right?) there is no current being induced in the mags. It acts just like an inert lump of magnets and copper wire sitting there doing nothing - so there is nothing to "burn out".
This is where it pays to have a fundamental understanding of how your systems really work.
Won't hurt a thing on the mag. Safety concern is that means the engine could technically start if hand cranked, but the mixture would have to be perfect.