Acne are generally caused by hormonal changes combined with excessive oiliness, bacterial growth and inflammation mounted by the body. Hence they tend to flare during teens, during stress, around periods, hormonal imbalances like PCOD, pregnancy to name a few.
Generally females over 25 years of age if have persistent acne or new lesions need to undergo a comprehensive consultation with investigations for any underlying medical conditions if need be.
Meanwhile use salicylic acid face wash. You can also use benzoyl peroxide 2.5% cream at night.
I would advise you to consult a dermatologist for long lasting results.
Dr Rashmi Lohiya
(MD, DNB, DDV )