I Don't Understand Shirogane-san's Facial Expression at All is a Manga/Manhwa/Manhua in english language, Comedy series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Yotsuya-kun joined the Discipline Committee in order to get closer to Shirogane-san, yet he can't read her facial expressions at all. Shirogane-san is always hiding her face behind her mask, but what may be the reason? Rom-Com shenanigans ensue. The first-ever serialization of the popular Twitter artist, Byte-sensei.