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If high dose oral antibiotics don't work, I often discuss accutane or spironactone or birth control pills. If those aren't indicated or acceptable to the patient, I also discuss and consider photodynamic therapy, smoothneam laser, Isolaz acne treatments and chemical peels. If your dermatologist doesn't know all the options for acne then think about getting a second opinion. Cystic acne is very treatable so don't lose hope.
If your antibiotics have not worked for your acne we do have other treatments. We can use Accutane, Spironolactone, birth control pills and several lasers can really help your acne. My favorite lasers are the N Lite (also known as RegenLite which is a pulsed dye laser) and my IPL (Photofacial). I have had very severe acne patients respond beautifully to the laser treatments . These laser treatment are painless . So you can see we have many more options to help you.
Please don't give up. If your Dermatologist does not offer these choices consider getting a second opinion.
I suggest you see a dermatologist with some experience in treating nodulocystic acne. Accutane, maybe with antibiotics by mouth or Aldactone would give good results in your case & prevent scarring/further scarring. After the acne is controlled, any residual scarring can be managed via Fractional CO2 laser.