This is going to sound strange, but I love the small details that emphasize the depravity of her situation. I've never seen dandruff used in manga before to signify neglect. Moka comes home to half-eaten cup noodles owned by her mother. There are clothes and flyers haphazardly hung on cracked walls. Hana is perfectly groomed, while Moka is the equivalent of a wild child. The collar of her uniform is open, showing the divots of her bones because she's malnourished. It's implied that her mother's boyfriend might have assaulted her because it happens directly after he was creeping her. Her mother yells at her to 'stop stealing' her man, like Moka tempted him to assault her.
One of the worst methods of child abuse is direct exposure to sexual activity without filtration. This is not a bashing of sex-ed class, where everything is carefully monitored under adult supervision. However, if you're exposed to sex as an elementary schooler in such a manner, I can't fathom the amount of trauma it inflicts. It distorts your perceptions of sex, especially when Moka is a daughter. I wouldn't be surprised if one of the reasons for her sexual openness is due to her past of abuse (not to claim that sexual openness is only due to trauma), but it aligns with the juxtaposition of Moka and Kazuki.