I had never really considered myself a self-harmer until I realized that was what I could call hitting things in order to feel pain so that the tension inside my head would lift. I'd never hurt myself much, a scraped knuckle on a brick wall, nothing serious, I don't like physical pain but sometimes my emotional turmoil demands it. Slapping myself in the head worked. I used to wrap a rope/thick shoestring around my neck when I was feeling that way. I haven't done the latter in quite sometime, I think it's because the chair on which the rope was tied for the cats to play with was moved and the rope taken off. So there's something to be said for removing the self-harming implement, whatever it may be.
In June I was so distraught by things going on inside my head that I punched the bathroom sink cabinet three times as hard as I could. Before I knew it, my middle knuckle began to swell and two knuckles turned purple and my thoughts cleared. I laughed. And then as my first real experience of physical pain transcending emotional pain kicked in, I realized I didn't want it. There was no way to make the physical pain stop. I sat in the bathroom holding my hand and then went to the freezer to get something to bring the swelling down. My hand didn't stop being sore until weeks later. From time to time I still feel a twinge of pain from that knuckle, I may have damaged the nerves. The next time I had a real opportunity to self-harm again I didn't do it, because of knowing that it would only make things worse in the long run. I suffered through my emotions. Yet I still found myself recently trying to slap away my distress. Since it wasn't serious self-harm, I didn't stop myself.
I'm sorry I don't really have any advice since I have a very pale case of SH. What helped me restrain myself from further injury probably won't be of much use. But if there's any way that a weaker act of SH could help you through your day, perhaps you could resort to that instead. (A very weak act is digging fingernails into the flesh of the palm, I do that all the time.)
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Let us comfort each other, and move tenderly when we are able. Let us hold hands and walk bravely, or fearfully together; for as long as there is Love, there is Hope, that everything will be okay, including the things we say are not.