Appearance of acne or continuation of acne beyond 25 years of age is called adult acne. Adult acne is most often associated with hormonal imbalance, stress, inappropriate use of skin care products etc.Most common causes include PCOS in women, insulin resistance, certain drugs etc. Treating the underlying cause is important for desirable results. Thorough history, analysis of skin, review of the drugs used, blood investigations may help a dermatologist understand your skin and make a proper diagnosis for satisfactory results. So please consult an experienced dermatologist. You may also need procedural treatments like salicylic peels, comedone extraction along with topical and oral medications like retinoids, hormonal medications.