Wounds

Why do wounds itch when they're healing? The usual reaction is to scratch. But, that doesn't help in healing, that tears up the delicate tissue, opens wounds, and can introduce infective elements.

From an evolutionary perspective, what is the point of that itching sensation when wounds are healing? What purpose does it serve, except to drive us crazy and make the wound worse?

And, if you want to know, I'm talking about last week's burn. It's driving me crazy. If I didn't keep it bandaged, it would not look nearly as good as it does right now.