This is just a diagnosis. It's either a panel, connection or board problem. If there is no warranty then depending on your skill you either have a TV repair person look at it or try unplugging, replugging internal cables. After that cable it will either clear up or tell you that a board or panel failed. Panel failure are the end of the set. Board failures are rough since parts on TVs moved across borders are sometimes not in country so you are dealing with paying for importing parts you can't be sure it will fix it.

This is another case that shows where going outside the local market burns up any savings.