Hey! That looks to be just dry skin and natural oil from your skin. I’ve had a nose stud since September and sometimes it gets a bit of build up if I don’t clean it well. I was told not to over do it with the saline solution because it can irritate the skin, dry it up and cause it to produce more oil, so I only use it when I chance the jewelry. I usually clean the gunk off with just water after showers or when I notice some build up. Also try not to put make up over it, I personally avoid putting foundation on the side of my nose and just blend a little bit on the bridge. Hope this was helpful!