After a household power blips during bad weather,... Sometimes the horizontal lines aren't bad

Question

Sometimes the horizontal lines aren't bad other times they are worse. They are dark lines that interfere with the picture, and sometimes portions of the picture associated with the horizontal lines are displaced . Please help... we really can't afford a new TV or a costly repair now...Hi I have horizontal green lines (spaced evenly 1 inch apart) over the tv screen. Particularly noticable on dark areas of screen. It's a CRT Tv - about 4 years old.
It seemed to start after power blips a few days ago due to bad weather. Also child has been playing with a large magnetic near tv. ( I read somewhere that this can cause problems) Any ideas about what has caused this and is there any cure?