Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain Acne can occur due to a number of causes like oily skin, hormonal imbalances, bacterial infection, inflammation, clogged pores etc..
In your case oily skin and hormonal imbalances can be a cause..
I would suggest you to start washing your face with Salicylic acid
and glycolic acid
You can apply creams containing Benzoyl Peroxide
You can also apply Azelaic acid containing creams..
Exfoliate your skin twice a week with a gentle scrub..
Do cool compresses on face..
You can apply creams containing Kojic Acid, Glycolic acid and arbutin to reduce dark spots..
You should limit sun exposure and oily food..
Take more of green leafy vegetables and fruits in diet..
You can also go for treatment like Microdermabrasion
and chemical peeling..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.