What do i use for the light source of my iguana?

i have had an iguana for about 2 months now. it is very young and it is about 10 inches long. green with a sorta brown tail. the store i had bought it from told me to leave on the white light on 24-7 and only turn on the heating lamp in the day. i have the two in one lighting source where i can control both. now i have been leaving the white light on with the uv off at night. is this bad for the new iguana and is it bad to change it now??