I'm a well read technosexual who's bluntly honest about all things, although I try to be most honest about myself.
"Ren grew a tiny, hopeful smile on his face that immediately transplanted itself onto my face too."
So just to be clear, his eyes are sliding off her face, her eyes are sliding off his face, and his smile is transplanted onto her face, but also is on his face, too. Also, he grew the smile.
I know I'm nitpicking, but seriously? This whole sentence is a mess.