Not sure if I have any suggestions for the OP mostly because I totally ignore / discount my T's expressions.

She usually has a "I'm-trying-to-focus-really-really-hard-to-solve-this-Math-problem" kind of face -- which isn't what I have (it would put way too heavy a strain on my facial muscles to keep it up for the hour as she does).

Once in a while, if I show any positive emotion, I guess she attempts to reflect it and smile but that's it.