I have relatively clear skin and usually have a small acne once in 4-5 months. I had one last week and not sure what the cause is. I still eat some dairy and I've also been eating dark chocolate. I'll have to eliminate them and see.
I suffered with cystic acne all through high school. It was devastating to my self-esteem. I found out last year that chocolate was my trigger. Once I completely eliminated it in any form, my skin has stayed clear for a year! (knock on wood) And the one time I had a little tiny bit of it, sure enough the next day I got a nasty acne cyst. Lesson learned!
Paleo has been great for my face, for the first time I can just use water to rinse it twice a day, and that's all I need! No products or anything. It's been wonderful.
I have just recently started to add in 100% grassfed raw dairy, haven't noticed any difference yet but it's only been a few days.