feeding problems

yesterday was my bp's feeding day but he didnt accept the mouse so i left it in his cage overnight. This morning i checked on him but the mouse was still there what do i do

Take it out, throw it away, check your temperatures and humidity/husbandry and if it's good you wait a week and try again.

Consider replacing your bedding and cleaning the cage good. In just one night, a mouse can create a whole bunch of odor.