On Razor V3, screen suddenly black, BUT keyboard lights up
I'm sorry to hear about the bad news. Unfortunately Razor phones are notorious for having malfunctions (hardware failure).
Your screen has been damaged, any number of things could have happened from just a manufacturing defect or sitting on it, dropping it the list goes on.
Basically you will want to get a new phone as there is not much you can do about it. When you replace your phone you can take the sim out of the one you have now and can put it in your new phone.
Post back if you have any more questions, Thank you for trying Fixya!