I'm a guy and I had a Perioral Dermatitis. You know what completely cured it? Vitamin B, more specifically "Biotin", which you can get anywhere. Another thing that helps to cure it are "Probiotics". Include these in your diet or buy as supplements. Plain and simple. Try it. I already helped my friend who had exactly the same problem. Let me know if it helped.
I've found that taking the supplement Biotin cleared up my perioirial dermatitis!!! Hope this simple thing helps someone else! :)