What do I do there is a bat jn My home with no visible entry points. What do I do

Turn out every single light in the house.
Open two doors.
Go outside and turn your car lights on.
The bat will leave.

Hope you got him out. As far as visible entry points, when I had a problem with a couple of bats getting in many years ago, I researched the problem as much as I could. One source said that bats can get through an opening as small as five eigths of an inch. The recommendation was to put oakum material in to fill any such openings, especially along fascia boards near the top of the house.
It was claimed that bats did not like the odor of the material in addition to blocking the openings. I don't know if that is a recommended approach nowadays but it worked for us.
Oakum Jute for Caulking (http://www.pollardwater.com/pages_product/p642oakum.asp)

Thank you all for your suggestions