I have a spot on the back of my shoulder that feels prickly when anything touches it lightly. (clothes, back of chair, couch, etc. No rash or visible markings, no selling, no color. I used a chinese herbal topical for months that didn t work, then plain vinegar which seemed to work. I stopped applying the vinegar after a couple weeks of the feeling disappearing. It went away for a couple months and now is back. Seems like it s a spring/summer thing? How do I get rid of this permanently?