If you can see the top layer of your Force Touch sensor among the display adhesive, it means the two layers of the sensor separated and you're going to need to replace or repair it.

iFixit screen and battery repair kits come with a replacement Force Touch sensor, so if you got one of those, don't fret.

The top layer of the sensor may be adhered to the back of the screen—if so, push it back down and separate it.