For what it's worth, stop having her take Accutane! That drug is just too powerful to do more than once or twice. I'm comforted by the doctor's post about antibiotics possibly working better than they did pre-Accutane, because I just now started antibiotics myself after having taken a course of Accutane four years ago with questionable results. The idea of a year- or two-year-long remission sounds heavenly to me because I broke out in tiny acne all over my forehead the month after stopping Accutane. Anyway, your daughter is lucky to have you helping her through this emotionally-draining effort to reclaim her beautiful face. I wish you both luck!
This is a difficult problem. It is possible to take Accutane a third time, but as you realize, the chances are that any remission will be short, and since your daughter is only 18, she can't very well keep taking Accutane over and over. Lasers may be worth a try--they're safe, but results are often partial and brief. Oral and topical antibiotics are probably worth at least a try. Even though they didn't work before, they may be more helpful now that Accutane has modified the oil glands, at least partly. Other possible therapies are oral contraceptives and the drug spironolactone. Your daughter should take up these and perhaps other therapeutic possibilities with her dermatologist.
Best.
Dr. Rockoff