To add to what Samicat said, anything cold can help release those same endorphins. I've been recommended keeping an orange in the freezer to roll on wherever you want to self harm, dunking your head in cold water, taking a cold shower, going outside if it's cold out, or ice packs.

Intense exercise will do the same too so maybe doing a reasonable, but still pushing it, amount of jumping jacks, push-ups, sit-ups, or crunches?

Then you could do opposite action and do self-care.
Whatever you want. Nice hand lotion? Go for it. Deep breathing? Hell yeah! Going for a walk? If it's safe. Talk or write about what's bothering you? Doooo iiit (we're always here to support you if you want to check in here )

Sorry it took so long to respond. Didn't see the post