I had had this problem when I was using ios 10. I had to reset the phone after installing 11, that fixed my problem not sure about you. I would just plug the phone to a computer with iTunes, launch iTunes, select your device, then if you have important photos take them off, then after pulling all the photos you want to keep select restore device/phone what ever it says just reset the phone . Hope this work for you :)
I sounds like the LCD has a loose wire from the MotherBoard because there is a backlight, but that's not always the case . If it's not LCD that has gone out not the digitizer it would be a cheap replacement.
Don't worry I have had the same problem. The only problem with this is that you will have to erase all the data and if this doesn't work it's something else. what has happened is that the boot up function has crashed so you have to reinstall the software. You must have a computer that has iTunes. If you don't have it on your computer install it then launch the application and sign into iTunes. With iTunes still open plug the iPhone into the computer hold down the power (sleep) and the home button down until it connects to the computer and enters restore mode (The iTune symbol should show up onto the display of the iPhone). After you plug in the iPhone it may require an update if so update it and restore the iPhone this should be an option in the restore mode menu. After that you need to let the iPhone restore. After the process is complete re setup the iPhone and it should work correctly if not, comment on this post saying it didn't work
Jay, I'm really sorry about your iPhone but with a bend in the iPhone you would have to do a lot more than replace the screen. You will have to replace the back of the iPhone and the MotherBoard and a bunch of other little thing because they are probably bent to. I'm supprised your Phone still works because were the bend is is almost were the sin tray is, the MotherBoard and other things. I know no everybody has cash to play with but I would get a new iPhone. Sorry if you didn't find what you were looking for.
To put the iPhone into recovery mode you must plug the iPhone into a computer with iTunes, after having iTunes open and the iPhone plug in, hold the power button (sleep) and home button until iTunes opens the recovery mode for the iPhone. If you need to restart hold the power button (sleep) and home until the iPhone reboots. Also the SIM Card my be damaged (all it take to destroy a SIM Card is a scratch on the chip) You can also setup the iPhone through iTunes hope that helps :)