Go into Facebook on a computer, and go to your timeline (or wall, whatever they're calling it these days. The page you get when you click your name or profile image. From there, click on Photos (under your Cover Image). Now click on Albums.
Look for - but do not click - Profile Pictures.
What is the image showing there?
In my experience, that image is the one that the Me tile picks up... which is a bug. It should pick up the latest image within that album.
If I'm right, you will be seeing the image that your Me Tile is displaying. Now go ahead and click to get into the album, and click the image you're using as your current profile pic. Beneath the image, click Options, and select "make profile picture." It'll give you some warning about having used this image before. Just tell it to shut up (or whatever) and click yes.
Now go back to the albums page and see if your profile picture is the Profile Pictures Album cover image (that thumbnail we were looking at before, which was probably showing the wrong image). Is it the right one now? If not, repeat this last step until Facebook stops being a &*$%ing ***** and makes the switch. Once it does, head on back to your phone and hit your Me Tile. Click the image in there and see if the magic happens.
I truly hope this helps. I've used this method a few times in the past couple of weeks, myself.