acne can be caused by a variety of causes like hormonal imbalances, stress etc.
the bacteria most commonly associated with acne is Propionibacterium acnes.
here are a few things you can consider.
1. drink upto 4 litres of water a day.
2. wash your face upto 3 times a day with mild soap or facewash.
3. avoid oily, spicy and junk foods.
4. excercise/yoga/meditation will help you by keeping the stress and hormonal levels in check.
5. apply clindamycin gel on your face in the night and wash off in the morning.
6. if it still persists, consult a dermatologist in person so that he can examine you and you may require oral medications.
you may also go for chemical peeling, that will remove the pimples and marks as well.