My 20 yr old son just noticed what appears to be a dent across the top of his head and upon looking at his skull I noticed a pinkish line right along where the dent is. Then I was noticing that he wears his headphones every day and they seem to sit on his head right along the same spot. They aren't really heavy headphones or anything - is it possible that they are causing this "dent" because he wears them every day?