thanx meshue, I hope I see it finished too

but first got to solve this problem, maybe you guys know what to do.

I want to make the mouth, and I selected some faces and extracted them.
this goes well untill I want to rotate the lower part. It gets all
funky. tryd to change the pivot but it still doesen't work.

anyone got an idea what is going on?
...or knows a better way to get the same result?