My 6 plus screen is cracked, and only about half an inch all the way down on the side shows my screen (sometimes it doesn't, the rest is black with colored lines running down it though it also changes colors sometimes). If I drag my screen down for the notification center I can kind of see it bounce down alittle for a moment.

How do I know if I just need a new panel (about $26) or an entire screen/LCD replacement ($100+)?