If they did not turn Purple yet, they wont do..... Ive grown dark devil . 5 plants, One remained green, and the other 4 showed different tints of Purple from darkpink to nearly black. Wich Color you get or if you get at all is genetic. But the differeence between day and nicht temperature brings alittle Purple too.
So if you have " Cold temps at night… the Colors will Change, If one week is enough to Change i doubt. But this is slowing down your buddevelopment// maturating too.
So i just would let it like it is