Try using Illumask (the acne version) to get you through the first 2 - 3 weeks when you start caveman. You can buy Illumask (light therapy) at walmart.

I started caveman and on day 1 used illumask because i wanted to reduce the so called purging/breakout/adjustment period your face goes through. I used the mask once a day (just follow instructions) and followed strict caveman for 3 weeks. I did not experience the awful transition period a lot of you describe. My skin got clear and after 3 weeks stopped the illumask but maintained caveman. I left 1 week of uses on the mask just in case i needed it. Im happy to say i havent used the remainder of my illumask and have been on Caveman for 2 months now. Just like many others here, I have the best skin ive ever had.

Just thought this might be helpful for those scared of the transition period. Illumask is really the only thing that you can use without interfering with caveman. And i probably wouldnt use Illumask beyond the transition period.