I can answer this possibly better then anyone...
I went primal on April 5, 2010. I had acne at the time and wanted to do an acne primal experiment. I had an acne blog at the time so this was a fantastic idea. My skin started to clear up more and more and by the summer it was just about gone. I then started to binge eat on junk food and was not fully primal for the last few months of 2010 and into January of this year.
I just completed a 30 day paleo challenge about 5 days ago. Everything went great. My skin wasnt "great" during the first 3 weeks and then started to clear up little by little. It is now just about back to where it should be - perfectly clear. I get the occasional teeny tiny whitehead.
I have 6 years experience with acne. I have learned that diet plays a massive role but one must manage stress, get adequate sunlight, sleep, etc. Basically one must follow the 10 laws of the primal blueprint (weird how it is just about the "cure" for everything). I personally believe that managing stress is way more important then most people think.
Continue eating the way you are eating and remember that diet along with stress are the biggest factors. Sleep, play, sunlight will help manage stress.
Also, your body is probably going through a "detox" and acne is a way of your body getting rid of toxins. Be patient - it should go away very soon.