What Causes The Peeling Off Small Dark Patch?

Hi. I was cleaning my pantry 2 weeks ago. a day or two after, i developed some skin patch, it was dark then with time it started to peel off. I had found a lot of weevils in the pantry on my beans and other grain. I put some aloe vera but the patch is still there, though it has really peeled off, today the skin seems to just be falling off on its own.

What could this be?