My television picture is in shades of mainly lilac & green. Any help or advice please?

If this is a newer HDTV, I hope you have a warranty.. However, you might try going to the 'picture' controls, and adjust the 'color' control..(Normally set in the middle at 50.) Some sets also have a 'color tone' setting.. Try a different setting. I have my color tone set to WARM-1