Fuzzy and Flickering Screen on Inspiron 5559

Despite the laptop being fairly recent and well maintained, I have a growing fuzzy and flickering screen on my Inspiron 5559; I have tried all online resources, BIST, rebooting the machine, but the problem remains. Sometimes, the line (mostly horizontal for the large lines, but also vertical for the thin lines) are flickering, showing a double screen, sometimes, they are stable. The problem is getting worse and when the screen is flickering, it's impossible to use the latptop. I have plugged the laptop onto a TV (via HDMI) and there is no issue with the picture on the TV Screen. Any clue on how to resolve this issue ?