Is detoxing a good method to shrink the cyst and I also haven't had a period in 5 months. I read about vitex is a good natural hormone balancer??

Beware of sellers of vitex and their claims - read sites that have no vested interest in the herb. I can find no reason why you can't take it safely, but you should always tell your doctor about any supplement you take. Some women claim it helped them, a few say it makes them too nauseous.
I can't see any reason why detoxing (whatever that means to different people - there's no one definition) would shrink a cyst. There are many kinds of cysts and kinds of matter inside them, all factors in how easy it is to get them to shrink vs grow or stay the same.