The only subplot I didn't care for was the one with Lisa Kudrow (the counselor / teacher's wife).
The idea that she'd just let a student take the fall for her wasn't executed well IMO. She gave that line, telling the girl she wasn't a whore because if she was she'd never be able to admit it. THEN, she just lets her go ahead and potentially ruin her life anyway. Something about that scene didn't fit well.
The 22-yr old BF, didn't really work, either. He wouldn't still be in HS at 22, no matter how many times he'd flunked. It was a point I couldn't get past - especially - once we learned why he was still in school.
STD's are serious business, and require reporting to the CDC, so the shrug off when the MC's named as the school's Typhoid Mary was off.
And the big reveal moment to the counselor's favorite teacher wasn't done well, either. It almost would have been better if the teacher came up infected, confronted his wife because he'd know that's where he got it, she admitted an affair, but still blamed the MC for the original transmission - then there could have been a scene with the "favorite" teacher turning on her for a while.
I DID like the movie, I just felt like the whole bit with the counselor was shoe horned in.