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.