Um, photographs are really hard to tell. Skin, huh? *Sounds* like an infection. Is the skin solid. That is, does it look like it could fold on itself. Does it look like if bubbles arose they would get trapped underneath. Does it look like a cockroach could walk on it. Of course, I'm asking you what it *looks* like. You shouldn't actually *try* any of those things! (Especially not the cockroach walk.) If you look *really* closely at it does it look like the growth goes in straight streaky lines? Is it chalky?