First of all wash your face with a non perfumed mild face wash like Cetaphil. Then apply a gentle moisturizer and exfoliated at least once per week with a mild exfoliating scrub. The treatment for acne scars includes various skin creams like hydroquinone, azelaic acid, corticosteroids, tretinoin cream and laser treatment. Apply hydroquinone cream on this scar and it should go away in a few days to months. If it still persists then you can go in for laser treatment, Chemical peeling or microdermabrasion. Avoid picking, harsh scrubbing, and abrasive treatments unless prescribed by a dermatologist during this period.
I hope it helps. Take care and please do keep me posted on how you are doing or in case you have any additional doubts.
I also have very oily skin and about a year ago started using Tea tree facewash. It helps with the impurities. Always use a toner and moisturizer after that. For the marks, i found that rubbing pure olive oil on your face at night works wonders. Use only the Tea tree facewash and then the olive oil. Also, eat lots of fruit and vegetables and drink at least 2 litres of water a day. That really helps. I can tell you from experience because i also used to have marks left from my pimples even if i dont touch them. Excercise also helps alot