Does it give you relief from mental pain?
Yes, I felt good when I cut but my case might sound strange.
In 2014 I started to cut my arm in order to attract medical attention.
I considered visiting a psychiatrist because I felt extremely low and I suspected I had depression, but I was afraid of being treated like a whiny teenager who complains about minor inconvenience, because I had heard "Feeling low during hard time isn't depression. Just keep going." several times. I was looking for a job then.
So I deliberately started to cut my arm in order to show how much I was suffering. I even practiced it several times until I got noticeable scar. Then I went to a psychiatrist and showed my scars. He diagnosed me with "neurosis" (the archaic name of "generalized anxiety disorder") and prescribed me a benzo.
But after the first visit to my psychiatrist I couldn't stop cutting for a while, because it felt so good. Physical pain distracted my helpless feeling. And it greatly alleviated my sense of shame - I thought I was mentally ill and deserve treatment, not judgement.
I kicked my self-harm habit in 2017 and benzos in 2020, but my right arm still has scars. I don't recommend anybody self-harm, but that habit saved my life then.