First, make sure you are safe. If there is any doubt or fear CALL 911. Leave the house or area you are in if you are in danger. You can call to report from a neighbor's house, a pay phone, or a cell phone. Locations with the Safe Place yellow sign are good places to go.
You can report to the toll-free hotline at 1-800-800-5556 and report it yourself.
Mandatory reporting law requires anyone who suspects child abuse or neglect to report it. Tell an adult and they can report it for you (a teacher, a coach, a neighbor, a friend, anyone).