That was kind entertaining to watch with a great format/length. But that still lack of scenes between the two protagonists to create a real chemistry. By some aspects their relationship seems rushed.
The second issue I have with the story is the notion of ugliness that conveys this drama. Although they can't be completely blamed, they could have convey a more positive message.

Actors was great even if the main actress seemed awkward with skin closeness/kiss. But she is 19, and age gap between the two actors can be a factor.

This kind of story with the same pace and more maturity would be a great romantic drama.

OST : not memorable but not annoying
Re-watch value: I rarely re-watch a drama.