Hello, I Have An Infrequent But Recurring Vertical Bruise Or

Hello,

I have an infrequent but recurring vertical bruise or scratch that appears above the bridge of my nose between my eyebrows. It is about a half-inch long, and no more than a quarter inch wide. I do not wear glasses, use any cosmetics, or take medication. I am 42 and have had this appear every couple of months or so for 5 or 6 years now. Any idea what this is? It doesn't hurt, but is unsightly.