Given the symptoms, the only thing you can do is to get a repair center to look at it. It sounds as if something in the picture tube drive circuits (such as the cathode cutoff) and/or deflection has failed.
Of course, these things always happen when you point out their absence. There are actually three orders of severity to Murphy's Law;
1st order: Something bad happens only because it can
2nd order: Something bad happens even though you tried to prevent it
3rd order: Something bad happens
only because you tried to prevent it
So, if it makes you feel any happier, you were struck by a Murphy of only the 1st order.

I usually get 3rd order Murphies.
I wish you the best of luck in getting the set repaired and that it won't set you back that much. The TV is young enough to be well worth repairing.