So many of my acne patients have it in their heads that they must moisturize their face daily.  Acne is partly caused by overactive oil glands which leads to clogging of pores. 

 Moisturizing actually traps that oil under the skin, so it can potentially aggravate acne. 

Use of moisturizer should be limited to days when the outer layers of skin are getting too dry, or to counteract the over-drying side effect of certain acne medications like benzoyl peroxide or retinoids.  And even then, the moisturizer should be used very sparingly. 

If the acne meds are causing too much dryness and irritation, then decreasing their use (for instance, once a week instead of daily) will still allow them to work but cause less side effects.