Thank you for asking. I can understand the distress you are through. Firstly, let me clarify that back pain and pimples could just be a co incidental with u our problem of masturbation. Masturbation is unrelated to these issues. Masturbation does not cause weakness, pain, or pimples. For masturbation habit, you must consult with a sexologist for further management. The frequency is not healthy and can risk you for development of sexual dysfunction in future. You can discuss the problem of back pain with him too.