the clearance between the bottom of the screen and the 'top plate' (where the keyboard sits) is very small, and the hinge geometry turns that area into a nutcracker if your Mac is closed with anything in that space.
If you purchased AppleCare Plus, that damage will be covered with a modest co-pay, about US$99 if I recall correctly. If only the bezel is cracked, and not the active part of the display, it may also be covered in a similar fashion.
If this is not damage to the active part of the display, some readers have covered it with one layer of vinyl tape (electrical tape). There are now third-party replacement bezels available as well. Check eBay for availability.