I've taken products containing icariin, and like any testosterone boosting product, oily skin and acne can be side effects (the most I have even noticed is a few larger pimples on my shoulders/back, not really face. I have never really encountered oily skin though). However it is very "unpronounced" compared to the average individuals thoughts of steroids that produce similar side effects but in greater quantities/visibility.
Accordingly though these products contained additional natural hormonal influences so to directly atribute the side effects to icariin is not possible, but since it is one of they key parts to that then the above stands.
Are you taking icarrin solo, or a formulated product?