No problem.
The male hormone testosterone. More specifically, it's a specific testosterone called DHT. This specific hormone, when produced in excessive amounts by the body creates an environment for the oil glands to go into overdrive producing the natural oils that normally protect and moisturize the skin.
"Excessive" serum levels of Testosterone and/or DHT are not alone a sufficient indicator for hormonal acne - the type of acne you are speaking about. What is of equal or more importance is the level and type of steroidogenic enzymes the affected sebaceous gland or dermal papilla contain. For example, while an individual may over-express testosterone, this over-expression may have a negligible effect on sebocyte proliferation depending on the level and subtype of 5-alpha reductase the particular gland expresses - and "ditto" for the beta hydroxysteroids which are responsible for androgen interconversion. What needs to occur for hormonal acne to become symptomatic is not only sufficient serum levels of DHT/Testosterone, but also sufficient enzymatic activity and ARS expression [DHT binds to an AR expressed in the nucleus of the sebocyte, causing it to proliferate - not necessarily produce more sebum]. Thus, and as I said previously, serum levels of the chief androgens and acne are insufficient indicators of one another. More on this below.
It's basically a case where your body's natural protective mechanisms are corrupted and begin to work against your skin rather than protect and moisturize it, as nature intended.
Yes and no.
This testosterone overload is precisely why the best acne treatments are aimed at helping to balance the hormones again, so that can facilitate the natural equilibrium between estrogenic hormones and androgenic hormones that should exist in every man and woman.
No, and you may need to deepen your understanding of how it is that the sebaceous glands - the oil glands you have been referring to - operate.
Sebaceous glands have a complex regulatory system whose proliferation/mitigation cannot simply be reduced to fluctuations in serum androgen levels alone. Sebocytes - the cells which comprise sebaceous glands - react not only to fluctuations in androgen levels, but also to fluctuations in levels of insulin, cortisol/cortisone and their corollaries, TSH/T3, ACTH and a range of pro-inflammatory compounds known as cytokines; and furthermore, there are several non-hormonal pathogenic factors which are indicated in the development of both acne and seborrhea, including bacterial proliferation and seborrheic infections. Because androgen use is implicated in a wide-range of the body's physiologic and metabolic functions - including the release and distribution of all the hormones I listed above - the presence of post-administration acne is not a sufficient indicator of serum androgen levels. Without getting too technical, your acne could be the result of a wide-range of pathological processes not in any way related to serum levels of endogenous testosterone or DHT.
Then looking at libido and test. We know when men have low test levels they have problems with ED, ejaculation and low sex drive. Hence why when on a cycle of test your sex drive goes into overdrive. Then you come off and your natural test production is dimished which leads to the above mentioned problems. Then as natural test production increases you slowly get your sex drive back. And when all your hormone levels are restored you are back to your self.
Far too simplistic. Sexual function and desire are complexly regulated systems depending upon a balance not only between androgens (DHT:Testosterone) but also of androgens and thyroid function (Testosterone: T3/TSH), androgens and estrogens and progestins, androgens to cortisol, etc. All of which, unfortunately, are taken off balance by introducing excessive amounts of androgens into the body. "High" and/or "low" libido and the quality and frequency of erections are dependent upon far too many factors to simplistically reduce them to serum androgen levels.
Again, these "symptoms" are not sufficient indicators of how active and/or inactive the underlying physiological processes may be. The same symptom - acne, in this case - can have several different pathological causes, and thus its presence alone in no way indicates the level of any hormone, cytokine, or otherwise. And this is particularly true because you are not a dermatologist, and as a result, I seriously doubt your ability to distinguish between mundane acne, a seborrheic infection, folliculitis, and so on.
But I have found it is a good measure of letting you know your natty test levels are started back up.
Whatever makes you happy.