Is her period regular? If not, you should also ask the doctor about and to check for poly-cystic ovarian syndrome (PCOS) as well as getting her thyroid checked. PCOS can cause the skin darkening and skin tags and often goes hand in hand with thyroid issues.
Good luck!
I'd recommend having her thyroid checked. The darkened skin could be a hormone imbalance. Not sure about the little bumps - perhaps that razor irritation or ingrown hairs?