@abubakarkhalid1993 another way to change display assembly for free by apple. look for AR Coating problem. there are many case in MBP2017. Claim for that reason you will get the new display even no apple care anymore. I think you can claim for that reason until late 2021 because apple spare part for 4 years.
Same problem for me. In my case if you have no Apple Care and still don’t have money to change it at the reduced cost. (1) Use external Screen, you may feel your MBP has become a Mac Mini but when you spend time like week or month then back to using the internal screen, this problem will disappear! I can use my system for 2 days and the line doesn’t comeback but I can feel that my systems screen still has the problem. (2) Seeking for A.R. Coating issue on your screen. If you’re lucky enough to have this problem. Go to Apple Store and claim AR Coating Failure. Apple will change ALL screen parts for you, and yes it free!