I Don't Understand Shirogane-san's Facial Expression at All

Chapter 7.5: Extral,
Chapter 7
Chapter 8: 8
Chapter 7
Chapter 8: 8
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. Alternate raw: https://dengekidaioh.jp/product/shiroganesan/