I'm not sure if what you are experiencing is what I have but I thought it sounded kind of familiar. When I was about 17 I started to break out around my mouth and along my cheeks. My mom took me to a dermatologist who said I had rosacea (did I spell it right?) and prescribed me some medicated gel to put on my face twice a day and also a daily antibiotic to take. After a year or so of following that regiment I went back again because what I had been prescribed had no effect. The doctor changed the medication and I gave the new medicine a try. I went off to college and came home after my freshman year and still there had been no change. Went back to the doctor again and he told me he had read an article in a medicial journal about people with untreatable, rosacea-like symptoms actually having an allergy to fluoride. He suggested I stop using flouride toothpaste and see if that made a difference. My mom and I searched forever but finally found a brand of toothpaste that doesn't contain fluoride (its by tom's of maine). I tried it and within a week my skin began to clear up. I stopped using fluoride toothpaste 6 years ago and haven't had any problems since then. Actually, I have just a little on my chin but it is barely noticable and easily covered up by make-up.....I think it is probably from the fluoride they put in tap water. Anyways, fluoride ended up being my problem - the couple of times I had to use fluoride toothpaste since then, I would break out around my mouth almost within an hour after brushing my teeth.
I don't know if you have the same thing as me - mine kind of popped up out of no where too. I had used fluoride toothpaste all my life up until then. It could be possible that it is just a hormonal thing, especially if you are getting close to your period. Get an appointment with a dermatologist and have him or her take a look at it - maybe it is something that can be easily treated with some medication or, in my case, by using a non-fluoride toothpaste. Good luck!!
