Did losing weight also make more space in mouth inside mouth not outside like if cheek usually comes between teeth it also reduces cheek from inside?

There is very little fat to lose in your cheek, but if one was obese and then lost a substantial amount of weight, there might be a smidgen more room between the teeth and cheeks.

Works the other way. Cheeks thin from the outside in, not from the inside out. So no, there will not be more room, and teeth will not tip into these buccal corridor areas.