Taken from City of Bones book:
He bore little resemblance to the handsome boy in the photograph, though his eyes were still black. His face was not what she had expected: It was a restrained, closed, interior face, the face of a priest, with sorrowful eyes.
I've looked up it's meaning in several places, though, found nothing regarding features or face expression. Does it bear the same meaning as closed and restrained : not showing emotions? I also wonder if it's a metaphor and not how interior is normally used.