Just being observant, lol. I was looking at the white shine on her lips before and after and it seemed like it grew brighter after she licked them (she didn't move her face much so there wasnt a drastic lighting change). I could just be tripping.
And if they have any sense of plot twist, they'd make him inhabit the body of a poor (but beautiful) Japanese girl so he can feel competent, win the tournament, and justify his 'holier-than-thou' behavior.
It's a small touch, but her lips also appear 'glossier' after she licks them. Like the shininess increases.
edit: Having Tengu possessing her would actually be very cool. They could easily make a story out of that.. how she was an ordinary Geisha or something and him possessing her caused her...