Horimiya

At school, Kyouko Hori is known for being smart, attractive, and popular. On the other hand, her classmate, the boring, gloomy Izumi Miyamura tends to get painted as a "loser fanboy." But when a liberally pierced and tattooed (not to mention downright gorgeous) Miyamura appears unexpectedly on the doorstep of secretly plain-Jane homebody Hori, these two similarly dissimilar teenagers discover that there are multiple sides to every story...and person!

(Source: Yen Press)

Notes:
-Includes 20 extra chapters.
-The 17th volume got released on July 18, 2023. This was 2 years after its original ending. This new volume included 10 extra chapters.