I cut and am suicidal i went to my doctor to ask for help and she said she can't do anything about it, my mom said it wasn't important.i feel so alone?

Mom is WRONG: You need help and should have access to good mental health care. It does not say where you live but in most places there are teen crisis lines that you can call for assistance. If that is not possible, go to the nearest ER and tell the doctor you are suicidal. Ask to be admitted for psychiatric help. You should not have to feel this way and you deserve help. You are brave to have brought thisup to your doctor and your mother but neither seems to understand so you will need to seek help elsewhere. Is there another adult in your life you can go to? Do not hesitate to get help.