Book with an unreliable narrator

[mbh12]

I'm looking for a book about an unreliable narrator, I think she was a teen? She had a younger brother and her mom was a famous actress. I don't remember any of their names, I just remember that the blurb on the back cover was a bunch of lies about the narrator that she told her friends, and one of them was that she was a vampire?
I remember is as like a supremely average book, but it really bothers me that I can't remember the title. I think it was a YA novel, and I guess the plot was something along the lines of the girl going on a trip with her mom and brother, meeting a creepy boy and somehow learning that lying is bad?

Comments

[calzephyr]

How long ago did you read it and about how old were you at the time?

[rheasilvia]

Could it be Liar by Justine Larbalestier? Though if it is, I certainly interpreted it differently. ;-)

I don't remember this narrator's mom being a famous actress, though, so maybe it's a different book altogether.