Wow, I'm suprised you go them so soon. Your body must have rightly jumped into ketosis. I didn't get them till the last day of my water fast. I used to have somewhat bad Acne as a kid and teenager(started at 9), but that ended around the time I turned 20 and though I'll get a zit every now and then, it's nothing like the severity of which I broke out on my last day. They did go away after a few days though.
Since your body uses virtually every organ to assist in detox and your skin is an organ, that is one of the symptoms that you can tell your fast is working and there is less toxemia in your system.