I'm sorry you are struggling with this. I'm not unfamiliar with self-harm myself. Here's a link to an article, from PC's archives. It is a Psych Central Professional article. So it is targeted at mental health professionals. But I think the content is worthwhile for someone who is struggling with self-harm to read as well:

3 Tips for Helping Patients Struggling with Self-Injury

And then, also, I thought I would draw your attention to the "Sticky" at the top of the Self-Injury page regarding things to do instead to hurting yourself:

Things to do instead of hurting yourself

My best wishes to you...