Your daughter may have polycystic ovary syndrome, or she may just have hereditary acne.
It would be best to get the lab tests (your dermatologist will know what to order) and be sure. There are many options for hormonal acne. Yaz and spironolactone are two excellent options.
Tazorac is often more effective than Differin, and oral antibiotics are often effective. Laser treatments with Isolaz and Cooltouch have success as well. The treatment of last resort for severe acne is isotretinoin.
In the end, I think the best plan is to work with a board certified dermatologist who can review all your options and pick the one best for your daughter.
Good luck.



