If the display is working I would leave it alone.
You can't bent it back with the LCD display in place. Follow these IFIXIT guides MacBook Air Models A1237 and A1304 Display Assembly Replacement & MacBook Pro 15" Unibody Mid 2010 Matte LCD Replacement while the last one its not the same its close enough to give you an idea on how to remove the panel assembly so you can rework the metal lid.
In any case your skills & tools you use to reform the lid will mar it and the metal may be bent enough that it won't reshape back. Lastly, the metal will be fatigued so it won't be as strong after reshaping.
You may want to think about replacing it either the case alone or the entire assembly (new or used).