Hmmmm.... Once when I was in my mid-20s and living in NYC, a friend and I drove out to Connecticut to have lunch with a couple of guys we were dating. After lunch, we took a walk in the neighboring woods. At some point, somebody pointed out some poison ivy.
I laughed and said, "Oh, I've never had poison ivy; I guess I'm not allergic."
That was a mistake. We left a few hours later. I'd been well-covered; I was wearing jeans. But that wasn't enough. By late the next afternoon, I'd developed a horrible itch on my left thigh. There was no doubt what it was. I didn't have any calamine lotion. I didn't want to dress and go out to the pharmacy. I did have antihistamines, and took some, but they didn't help. I called a doctor I sometimes dated. He had no useful suggestions, beyond putting a bottle of vinegar in the refrigerator and dabbing the rash with it every once in a while.
That was not gonna cut it. I looked through the other meds I had on hand. And found a partly-empty bottle of Preludin pills. They'd been prescribed more than a year earlier when I'd had a regular physical and asked the doctor for something to make me lose weight. I didn't really need to lose weight, but you can never be too rich or too thin. So...
But I didn't like the Preludin. It made me feel sort of disgusted by food and eating. And I did still want to enjoy meals. And Preludin was said to be a possibly dangerous drug. I forget why, but it was taken off the market a few years later. I stopped taking it.
But there it was in my medicine cabinet. Why not? I was ready to try anything. So I took one. An hour later, the itch had stopped. The rash began to dry up. By the next morning, it was nearly gone. I was amazed.
So, if you happen to have any Preludin around... Though my real point is to try anything you think may work. That's what I do. Though probably it's stupid.