Dealing with black display lines comes down to isolating the failure chain before spending money. Run the external monitor test immediately. If the external screen stays clear, verify the display behavior inside your BIOS. If the lines disappear there, a clean graphics driver installation using DDU or adjusting your panel's refresh rate down to 60Hz will solve the issue without a technician.
If the lines persist in the BIOS, tilt the screen gently to check for mechanical cable pinch. Replacing or reseating an eDP ribbon cable costs under $40 and takes less than an hour of bench work. Reserve costly full-panel replacements for cases involving visible glass fracturing or confirmed internal controller failure, ensuring you never pay for a new screen when a simple connector adjustment was all your machine required.
