Periods irregularities. Get rid of acne!

I am staying in dubai and its very common problem faced by all girls is the irregular menstrual cycle. Before i was getting periods 2 days or max 3. But from last 3 months. Wen i get my periods its dark dirty blood on first day and second day and then light bleeding on 3 day and its over. Then again aftr 3-4 days bleeding will start which will be clean blood but for 5-6 days but just stains. Lyk in mrng then one stain in afternoon and at night. Not continous bleeding. I had my scan and i dnt hav polistic ovary. Drs here keep recommending weird medicines lyk contraceptive pills to my shock. Also it has lead to bad acne on my face which was never there before. So logically i m almost 10 days on periods in two shifts. If there anything to worry about this clean blood stains. And what should i do to basically get rid of acne