ohhhh noooo!!!!

The top of my plant broke by a small light falling on it what do I do? What will happen, will it die?

A pic would help but people "top" their plants all the time to make them bush out more. Probably be fine, might even turn out to be a good thing.

If it actually broke the top off, yes, consider it "topped", but if it is sort of just hanging there, you can tape or tie it back up and it will heal up fine within a few days. You can use a small piece of wood such as a toothpick or something to fashion a sort of splint, or, depending on the size of the plant and the top of it, you can tie a small piece of string to something above it to keep the top upright. Either way, it's not the end of the world.