I'm a 20 year old female who had been struggling with painful, cystic acne since early highschool years. I was once put on doxycycline 100MG when I was 17 and my face seemed to clear up almost immediately, and I was acne free for my senior prom 3 weeks after starting the medication. After now being off the medication for 3 years, I've started to develop cystic acne even worse than what I had before. After seeing my dermatologist, she suggested being put back on doxy since "it worked before." Now after 3 months I've seen ZERO improvement and have actually noticed the acne getting worse. I have been taking doxy in conjunction with a benzoyl peroxide face wash to prevent bacterial resistance. Could I be immune to the antibiotic? How long should I wait it out before seeking other options? The embarrassment is getting overwhelming.