Your symptoms started just as mine did almost two yrs. ago. Please check out www.morgellons.org to rule this condition out. It might just save you a substantial amount of money, time, and the frustration of those around you thinking your crazy.
I think your dermatologist is correct. I think you have a form of rosacea, and that doxycycline will do the trick if you give it long enough. Long enough means 4-6 weeks. I urge you not to change course until you've invested that length of time. Occasionally, doxycycline doesn't work, and other antibiotics need to be used. But in your case, I don't think you've waited long enough to tell. I'd keep up the Metrolotion too, by the way.
Take care.
Dr. Rockoff