4th flush, no stones and WORSE acne!Can I flush again?

Hi

I just completed my 4th flush at the weekend and got absolutley no stones out. I very much doubt that this is because they are all gone, as I have only had between 100 - 200 out in total!

What are the reasons for this? also, my Acne has gotten worse since then, I have read that if you dont get any stones out it is ok to flush again immediatley. What do you guys think?