I don't understand why kids don't tell.
I don't either, and I've been there. I was harrassed from the first day of high school (Standard 6 - 8th grade) to Matric (12th grade). I was depressed for the first two years, and I mean can't see any reason to go on, real physical symptoms, anything not to go to school (I must have missed a few months cumulatively). I did tell my mother, but to this day she just says, "I tried to warn you that high school would be different from primary school," as if I didn't listen to her and that's why I had to SUFFER for five YEARS.
My mother had white-blonde hair and was quiet, and she was constantly harrassed by her classmates in the late '30s/early '40s. But she says, "Well, I was so quiet, I brought it on myself." No matter what I say, she's convinced that she somehow deserved it, and maybe that's why she never got that I KNEW I didn't deserve that treatment, but also why she never thought to put me in a different school.
But she did go to the principal when I was in 8th grade - after I broke down crying that a boy in my class was harrassing me. And it wasn't too bad, just a nasty comment here and there, but after everything else, it was too much. But when I was called into the principal's office and told that my mother had visited him (we don't have guidance counsellors here), I just became angry and thought, "Why is she INTERFERING? Now everybody will know I can't hack it in high school!!" and I just mumbled some nonsense at the principal so I could get out of his office (I was only 13 at the time).
I think kids are reluctant to tell people because they're ashamed of the bullying, even if they know intellectually that it's not their fault.
I could have done a LOT more to fit in: cut my hair in a more contemporary style (my style was more like Louise Brooks, but I thought it suited me), taken my dress up (but I didn't like my school dress to be short as the skirt was pleated and if the wind blew, it would fly up around your waist), etc. But because they wanted me to, I just wouldn't. I could give stubborn lessons. OTOH, I've always marched to my own drummer, and even five years of torture couldn't make me change my tune. But you have to be a strong person to resist in the face of some of what goes on in a high school.