Usually good for about 2-4 hours
C is going to be the best answer to this question.
I think so, but not really but dark spots usually go away over time, instead there are creams made to use for the dark spots and it helps quite a lot. I can list some for you that I use such as Mdacne and hydroquinone cream I prefer hydroquinone cream more since its more effective and cheaper. Hope this helps:) Have a good day/night.
