Does hormone therapy completely cure me of endometriosis or can it come back?

Endo can come back. Hormone treatments are suppressive therapy, and don't cure endometriosis. Hormones can help in relief of pain and in preparation for more definitive treatment.
No. Unfortunately endometriosis is a chronic illness. The recurrence rate after surgery or medical treatment such as hormonal treatment is approximately 10% each year.
No. Hormone therapy will stop ovulation and suppress endometriosis while on therapy. Only surgery will cure endometriosis.

Related Questions

If I stop hormone therapy, will the endometriosis go away?

Hormone therapy. Usually helps suppress endometriosis but it depends on what exactly you are taking. If you stop the therapy, assuming you are taking Lupron (leuprolide) for example, the endometriosis will slowly become responsive to estrogen and Progesterone that your body will re-start making. I would speak to your doctor about your homrone therapy as it relates to endometriosis before making decisions to stop.