Thanks for using the Apple Support Communties. I see from your post that your iPhone's display is flickering a bit when you use it and you are looking for the best solution for this issue. I definitely understand how this can be a bother to you when using your iPhone. I'm sure I can guide you down the right path to find a lasting solution.
In this particular situation, I recommend following the recommendations found in this article called Get help with the display on your iPhone, iPad, or iPod touch. Take a moment to review the information found in this article and see if this information help.