Why does my Kindle have lines on the screen?
I can't read any of my books. Instead, there are just vertical lines across my entire screen.
The 2014 edition of the Kindle, part of the 7th generation, includes a touchscreen and same form-factor as the Kindle Paperwhite, but lacks the backlight.
While it is very possible that the display panel is damaged, your Kindle may only be affected by interference from more powerful devices, such as a printer or computer. After moving away from these devices, restart your Kindle by holding down the power button for 30 seconds.
If the lines are still there, then it is safe to say the display panel has been damaged as st3v3w described.
This information and more can also be found on the Kindle 7th Generation troubleshooting page.
Best of luck!