It is about this girl who ends up liking her teacher, the problem is she has trouble showing her emotions. (I remember a scene where she tells the reader that her face is currently at its most surpised... which was similar to her normal face except for a sweat drop lol)
I remember the teacher shouting "I LOVE TSUNDERE" right after he kissed the girl (hiding in the teacher's table).

😀

Could it be
Kinkyori Renai ?

that's it.!

thanks a bunch 😀