I haven't used my axon 7 in a long time, but if you look at pictures of the inside you can see where the display cable plugs in, if you just apply pressure to that area it fixes it. very common issue

This may be an old question, but here is an answer for other axon 7 users: Your display cable may be loose, so here is a solution without opening the phone. Hold the phone upright with the screen facing towards you, then pinch up and down the right side, you may or may not hear/feel a click, if your problem is not solved, then your screen may be permanently damaged.

Hold your phone upright with the screen facing you. Pinch the right side of the phone up and down, you may or may not hear or feel a click. your display should now be working. Edit: OMG I'm still getting emails from ifixit on this post, glad I could help you guys. I love taking apart almost every phone I buy and learning every nook and cranny