Can I put gorilla glass on a cracked screen?
You mean a gorilla glass screen protector? I don't see why not. I however wouldn't apply a screen protector that requires water, depending on how bad the cracks are you don't want water getting inside.
Good point. Thank you. I'm thinking about just buying a new case for the phone I'm stuck with this phone for a while and I want to try and hide the Crack the best I can.
Which device do you have?
Galaxy S4
If you are pretty handy you could replace it yourself for $25. I would only do it if you don't pay for insurance on the phone and you're beyond the 12 month manufactures warranty (which you are.)