I Cant Get Any Physician To Prescribe D.C. Dose Doxycycline

I cant get any physician to prescribe D.C. dose doxycycline 20mg q 12 I was on it for a year straight with no issues. It is THE only drug that works. Topical metro gel and erythromycin do not. Sulfur OTC helps a bit . I took amoxicillin for what was supposedly a bad tooth ( turned out to be T MJ pain.) Ten days of it clears the Rosecea up for two months.Why are they adverse to SD doxy? It doesnt kill bacteria at that dose and I take Florastor yeast probiotic to prevent any potential low risk of c diff anyway. Any suggestions?