Will hair come back after lowering testosterone levels?

It is possible that your hair will come back after lowering the testosterone levels, since the byproducts of testosterone are linked to female pattern hair loss. Remember that the hair cycle is about four months, and you need to wait a least four months before seeing changes. You might consider using finasteride as a blocks the DHT.  You may also consider PRP treatments to boost and stimulate hair growth. #StayBeautiful @RealDrWorldWide 

This needs an in-person evaluation. I recommend getting a formal evaluation with a hair loss expert to go over your condition and advise you on best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

Many women feel better with more energy, easier time losing weight, less depression, more libido etc with testosterone supplementation. UNFORTUNATELY, hair loss is very common with this supplementation due to the breakdown product of testosterone, DHT (dihydrotestosterone). Stopping the testosterone will usually stop or markedly diminish the hair loss but usually the hair does not regrow. 

I would need to know more of your story, see your scalp up close and review all youf blood tests before answering that. You require a full endocrine work up including evaluation of free and total testosterone, DHEAS, androstenedione, estradiol, LH, FSH. The history of sudden onset of rapid hair loss over two months should not be attributed to a hormone pellet placed 8 years prior with a full and complete work up to fully and completely rule out other potentially very serious causes of increased androgens in post menopausal women. Any female with testosterone levels three times above baseline needs a thorough and very detailed specialist evaluation.

Female hair loss is a complex topic, and your case may be even more nuanced than the space in this forum allows you to explain.  Testosterone can cause some permanent hair loss, but that does not mean you cannot recover and substantially improve your current level of hair growth.  
The best thing to do is to go to an experienced hair doctor or dermatologist.  Find someone who does NOT try to sell you a procedure or treatment, but seeks to give you an accurate diagnosis so that you can evaluate what treatment options are right for you.
Plus, as a woman who has experienced this herself, I know how tough it is to go through.  You are not alone. Good luck!

At 58 with high doses of testosterone, we have a model system that shows that genetic hair loss from testosterone (DHT) when it happens, is irreversible.  You might be able to stop its progression with the modalities you discussed above