Hormonal activity, such as occurs during menstrual cycles and puberty , may contribute to the formation of acne. During puberty, an increase in sex hormones called androgens causes the skin follicle glands to grow larger and make more oily sebum.  Several hormones have been linked to acne, including the androgens testosterone, dihydrotestosterone (DHT), and dehydroepiandrosterone (DHEA); high levels of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) have also been associated with worsened acne.  Both androgens and IGF-1 seem to be essential for acne to occur, as acne does not develop in individuals with complete androgen insensitivity syndrome (CAIS) or Laron syndrome (insensitivity to GH, resulting in very low IGF-1 levels).  
Topical hydrocortisone works much higher up in the skin. It is not a treatment for acne or acne cysts. In general, this category of products, especially its higher potency topicals, can carry side effect of skin thinning. As far as an acne cyst is concerned, it lies much deeper in the skin, and it is unlikely that a weak topical such as OTC hydrocortisone can reach it to have any significant improvement. The skin overlying the cyst surface is already stretched or thin to begin with; therefore, introducing any topical cortisone for its treatment can risk irreversible skin thinning. Another important side effect of cortisone to be taken into consideration here is "rebound or worsening of acne." Yes, these products can contribute to more acne.
Hi Rusiko, thanks for your comment. Natural Acne Clinic’s online clearing program specializes in getting our clients clear when nothing else has worked. Often products work for a little while, as in your experience, but begin to lose their effectiveness after a few weeks. This is because the skin adapts to a product regimen like your muscles adapt to a gym routine, and it is necessary to implement systematic routine changes in order to effectively treat acne. What makes our program so unique is that we change your skincare regimen biweekly over the course of 16 weeks, at the end of which our clients graduate with a clear complexion. We’d love to help you get clear too!