I never had any real acne as a teen either but I sure got it when I started dbol.
From my knowledge of acne in adolescents it is due to the following.
* High overall levels of sex hormones (mainly the androgen, testosterone).
* Increased free testosterone because of low levels of circulating sex-hormone-binding-globulin (SHBG). Normally there is little free testosterone circulating in the blood as it is tightly bound by SHBG.
* More active conversion of weaker androgens to stronger androgens such as dihydroxytestosterone (DHT) by the enzyme 5-reductase within the skin.
* Higher sensitivity of the skin to DHT.
All of which you will have an increased risk with taking AAS. However everone reacts differently to AAS hence stonecoldNTO advice.