Hello friend,
This happens. I'm sure we've all been there. If it's only partially snapped then i would tape it up and try to let it heal and support it with a kabob stick or something.
Otherwise if its a photoperiod plant then you can always cut it off and just consider it an accidental topping.😁
Mainly autoflowers i would definitely encourage tapping up and saving the branch because they really can't afford to lose much.