Hello Demetrios, so sorry to hear about your problem. What i would try to do if i was you, is unplug the battery, and test your old LCD back on the phone again. Plug the battery back in and if it comes on, then that means the new LCD is not compatible... you might have already tried to do that, and if you have, then it is possible your phone has got some motherboard issues. in the process of changing the LCD in the first place, hopefully you unplugged the battery prior to unplugging anything else. If you did not unplug the battery first, or at all, then it is a good possibility the motherboard got shocked. That could be a possibility considering that itunes picks up the device, yet it shows nothing.
I hope this was of some help, if you have any questions about what i have said, then please ask. Or if you have anymore more details about the situation, i can try to help out the best i can. Thanks for your time, and have a good day.