Is it against any rules for high school students to shave their heads?

I shaved my head for three years ... my teacher envied me. Make up an excuse at the beginning of school, folliculitis, fear of heat, too oily scalp, easy to inflammation. There is no rigid rule in the school that boys are not allowed to shave their heads, but they are not allowed to have long hair. But schools generally have a default rule that students should behave like students. What exactly is a student's behavior is a matter for school leaders. They think that boys' hair is good, that's good, short hair is good, that is to say, you should be short and girls should tie their hair, which is actually their aesthetic concept. Everything, in fact, is man-made, if you do something about it.