If you're American call one of these numbers:
National Child Abuse Hotline 1-800-4-A-CHILD (422-4453)
Child Abuse Hotline / Dept of Social Services 1-800-342-3720
Child Abuse National Hotline 1-800-25ABUSE
If you're not, call the hotline of your country, or ask for help to an adult from school or from your family