Light for my ball python

Dear all,

I wonder wether it is bad that my python has 24/7 light in its terrarium. I know that they need more or less 12 hours darkness but I only have 1 light and I can not dime that because it is otherwise to cold. He does have some sort of stone under which he can lay in the dark, but there is no real day/night ritme. Is this a problem?

Greetings