Get eczema, sometimes it can be quite bad but only around joints elbows knees neck. Turns out hot water is extremely pleasurable on it. Ran a hot bath as hot as I could take (wanted to scrub clean) once fully in it hurt momentarily then felt amazing. Like just past the early stage of a climax, don't want it to stop. Only last about 15 seconds though but keeps feeling good.
Pretty sure it's something to do with senses or nerves being overloaded and lots of endorphines/dopamine which ever, released in the local areas.
Pain elicits an endorphin response that in some cases can be pleasureable enough to overide the negative association. I haven't experienced what you have but can relate from a different context. When I lived in the US I used to get these little pickled hot peppers. They were crunchy and bursting with juice and melt your face hot. One of them and your whole mouth is completely on fire, but I would sit and eat the whole jar one after another and even though it was burning, it felt good, like full body high! That's the dopamine and seratonin release brought on as a pain response and it can be intense.
Pain elicits an endorphin response that in some cases can be pleasureable enough to overide the negative association. I haven't experienced what you have but can relate from a different context. When I lived in the US I used to get these little pickled hot peppers. They were crunchy and bursting with juice and melt your face hot. One of them and your whole mouth is completely on fire, but I would sit and eat the whole jar one after another and even though it was burning, it felt good, like full body high! That's the dopamine and seratonin release brought on as a pain response and it can be intense.
BTW, welcome to the world of S&M
I just started experimenting with candles/wax play and thought the same thing when I read the OP, that pleasure/pain can be delicious. Perhaps you could try out some other light bdsm as it sound like a positive response from you.
Also as someone who who has had skin problems we know it can be difficult not to scratch even when it hurts, similar thing I think, maybe.