A lot of skin problems are caused by Celiac disease. My sister didn't believe me that she needed to be tested for Celiac disease, but yep, she has it and going gluten free cleared up the skin problems she'd had since she was about 11. I had all sorts of skin problems too that improved immensely. I do like tea tree oil for healing skin breakouts.
That is a very interesting question, to which there is no crystal clear answer. Both medications are prescribed for acne, although orthrotricyclen is also prescribed as an anti-pregnancy drug. Both drugs interfere with cell wall replication and this can result in birth defects. The FDA site has an extensive evaluation on both drugs, which I suggest you read. A far better approach would be to culture the bacteria, and to determine the reason for the outbreak. High glucose levels are a common trigger. There is a rational argument for using two drugs to destroy bacterial infections. The downside side is that all antibiotics interfere with cell replication and repair. The FDA has a specific individual assigned to every drug. I would suggest an e-mail to them for a definitive opinion.