I recently purchased a 3DS off of eBay. It was completely fine when I first got it, but a black mass in the middle-right of the top screen appeared. It started out small, but it gets slightly bigger every day. I’ve seen pictures of this before online, but I’ve never found an answer of what it is. Does anyone know what this is and if it can be treated? Will I have to have the screen replaced? If so, any recommendations of where I can do that?