First of all stay strong. Then talk to any elder person about this matter. Usually, elder people should handle these matters and find a solution. As you said your father beats you mercilessly after coming home, which means, your mother doesn’t have the audacity to fight for you or maybe she is helpless. Then, your next elder person will be your close relatives. Ask them to help you. If anyone is not helping then you can reach out to your teacher for help and let the school take action accordingly.

Or you can take the help of the police. No doubt you said that your father is a policeman but that doesn’t mean that you can’t file a case against your father. To justify your case, try to gather evidence against your father. Take pictures of your bruises and gather any eyewitness who is willing to give testimony against your father. Once the police will take the FIR and will start the investigation then they will surely find out the truth about domestic violence. Then your father also might get suspended from his position. So, he won’t be able to mess with your life any further and the police will give you protection from him.

It doesn’t matter whether your father is a police officer or not, if he is torturing you and making you suffer then he is a culprit and he needs to realise his mistakes. You should involve your family members in this matter and ask them to keep you protected or help you in any possible way. If you do not get any help then you can file a case against your father under The Juvenile Justice (Care and Protection of Children) Act, 2000.