I LOVE my zeno, it has seriously saved my life. Although it says not to use on nodular or cystic acne . . . I did anyways. It has helped mine. It does not work as quickly on this type of acne, understandably, but the best part is the relief from the great pain of the bumps! The little blast of heat has helped numb the bumps greatly for me in the past, I have used it for this purpose several times succesfully.
Every time I have used the zeno for my nodular/cystic acne (to be quite honest, I'm not sure which one it is that I have. I think it is cystic, as the first time I had one I popped it not knowing any better) it has helped, and the bump will be gone in several days, a much shorter time than if I had left it on its own.
Occasionally I will have a bad break out with a lot of bumps, but mostly I just have a lot of small blackheads and whiteheads around my chin, and the nodular/cystic always occur around my chin as well--pretty infrequently, one every month to every three