I don’t know :/ there are a number of funny things I like to do (like push on my eyes when they’re closed, or press the corners of them going into my nose (near the tear ducts)) that I’m sure are not good for me but I like to do it. It’s funny, I have heard that if you get struck hard enough on your temple it could cause some severe damage (not to say getting struck anywhere is particularly nice) maybe it’s something to do with what it’s ‘made’ of. Wikipedia doesn’t uncover much, then again, I’m not a huge fan of biology, especially not the human body :)