I am a 14 student. I pulled it out with tweezers because I have leg hair. What harm will it do?

There is no danger, but it will grow out. The hair that just grows at first will sting, but gradually it will become more normal. Don't think too much, it will be fine.

Also, it is natural for boys to have foot hair. Girls don't feel like boys without foot hair, so don't pull it out again. This kind of thing is suitable for girls.