[She's done it! She's forced him on the defensive! He bristles up and folds his arms as he shrinks back a bit, in response to her new line of questioning.]

B-believe or doubt what you will! Such things are... completely foreign to me! This form's appearance is completely and purely a result of my own nature. N-nothing else!

And no amount of mere "moisturiser" c-can survive the toxins emanated by my very skin! These inquiries will bear no fruit... [He practically growls. But he's also clearly embarrassed.]