I removed a splotchy dye job with colorzap now my hair is light blonde which is what I was trying to achieve to begin with. Do I have to put a color back on or can I leave it like it is? Will washing drying sunshine damage it?

As far as I know, you do not have to color your hair if indeed you do like the color the color zap made you hair turn out to be! For most, their hair will turn a brassy orangish blonde color and coarse, in turn, they will definitely be using another color to dye their hair to achieve their desired look, for you, if you like it that way, by all means, stay that color and good luck! Only thing I would suggest is to heavily or deep condition it!