I dropped my phone (a 32gb refurbed 4s) in May of 2013. Cracked the back, and one side of headphones and Bluetooth do not work. (everything else is fine from what I can tell). Fast forward to a couple months ago and I now have this white shadow/mark that shows up when I open apps but disappears withing 5-8 seconds. Has anyone seen this? It's harmless from what I can tell and doesn't affect any apps since it disappears.