This was an unfortunate issue that ended up being somewhat common on several models of MacBooks in the 2013-2015 year models. It is an issue with the display assembly, either in the LCD panel itself or the inverter board. Either way the fix is to replace the LCD assembly per the [guide|45135|MacBook Pro 13" Retina Display Early 2015 Display Assembly Replacement|new_window=true] guide. You could try replacing just the inverter board (the motherboard that is attached directly to the LCD panel but that will require desoldering the ribbon cables that connect the board to the LCD panel which is very difficult unless you know what you are doing and can solder surface mount components. Also sourcing the board appears difficult as I could not find one.