Teen acne is very tricky as it is normally caused by uneven hormones. you should drink a lot of water and do not touch your face a lot as you could be worsening the situation with the germs on your hands. You could try over the counter products for acne like garnier and oxy face wash (which works very well for many people.) To remove the dark marks caused by acne you could try rubbing lemon juice on your skin daily,that could help.