There are various types of acne scarring.  The scars that have caused tissue damage are known as icepick, boxcar and rolling.

Rolling Scarring on both sides of chin w/some active acne lesions.

 Icepick and boxcar scarring

This type of scarring is difficult to treat as the tissue has been destroyed.  However, advances in medicine have resulted in some progress in treating this type of scarring.  Some of the options may be acne scar surgery such as punch excision, punch elevation, punch graft of subcutaneous incision.  Dermatologists are sometimes able to reduce the scarring with these procedures by replacing a deep scar with a smaller one that is less noticeable.  It may take time to notice a difference after surgery.  You will experience downtime for any of these surgeries.  In some cases once the skin has healed, other procedures such as laser or microdermabrasion may be performed to further soften the look of the scar.

Another option is dermal fillers.  These can diminish the appearance of scarring but most fillers are temporary and have to be repeated.  However, if you choose this route you can return to your normal activities right away.

Some minor scarring can be treated with chemical peels or microdermabrasion.  I do not recommend either of these treatments for severe scarring.  There is down time involved with deep chemical peels.

Since laser resurfacing came on the scene the original dermabrasion procedure is rarely done but still available.  This procedure needs to be performed in a hospital or surgery facility.  This treatment also requires down time.

You should always do your research and educate yourself when considering procedures to help with acne scarring.