screen flckering after replacement

I replaced the screen/digitizer on my daughter's Ipad mini. it powers on and seems to function with the touches etc but the screen flickers and looks horrid. It gets brighter and then dimmer every 5-10 seconds and you can see the previous screen faintly behind the current image, especially when the light gets dimmer. There are also horizontal and vertical lines distorting the image. I didn't glue down the cover yet and am wondering if maybe the LCD connector isn't seated properly. I am definitely not an expert (I replaced my friend's Ipad 3 screen quite easily) but this was so much harder! Any thoughts would be greatly appreciated.