Maybe you do it to feel something different, or at least to feel something. Could it be that deep down you are looking to feel something real?
From what I have studied and analyzed for a long time, many people commit SH because of immense sadness, anger, or as a way to vent emotional pain into something physical.
If you have doubts about what I'm saying, there is an experiment with painkillers, in which a person suffering from heartbreak can feel some relief after taking them, since an area of the brain related to physical pain is also related to emotional pain. But back to the subject,there are also people who SH because, otherwise, they would commit suicide in a very painful way because they would be desperate. I have seen this case, and this was my case, even though I haven't self-harmed in years.