Acne is not just a passing condition. Long after the acne is gone, scars in a variety of shapes and forms can emerge. Some common scar types experienced by patients include box and rolling acne scars. Fortunately, there are specific treatments and methods that can help improve the appearance of skin with box and rolling acne scars, which a DoctorxDentist reader asked about recently.
With expertise in thread lift procedures and acne scar treatments, Dr Ho Rui Ming serves as the medical director of M-Aesthetic Clinic. On DoctorxDentist, he shed light on the most effective ways to deal with acne scars. Here are our key takeaways.
What are rolling acne scars?
Rolling acne scars form when bands of tissue begin to develop in deeper structures of the skin's surfaces. They often cause rolling or wave-like depressions across the surface of the skin, making it look uneven and craggy. 
What are box scars?
These scars appear as round or oval depressions with steep vertical sides. Box scars are usually wider than ice pick scars and lead to an uneven, pitted appearance. Acne breakouts can destroy collagen and damage tissue, which creates a depressed area that eventually turns into box scars. 
A combination of scars is possible
Often, patients experience the emergence of more than one type of scar (especially if an acne condition has reached a certain level of severity). After the breakout, different scars may appear at the same time. 
It’s important to use a combination of treatments for a mix of scars
I recommend a combination of treatments in order to optimise results and smoothen the appearance of scars.
This can include a combination of subcision (+/- collagen stimulators) methods, fractional CO2 lasers, and fillers. In some cases, multiple sessions may be required with an interval of at least 4 weeks.
Subcision is a minor but often effective surgical procedure
This minor surgical procedure (also known as subcutaneous incisional surgery) is typically used when treating depressed scars and wrinkles. It is performed through a special needle that's inserted into a puncture in the skin’s surface.
Be careful of the frequency of treatment
Subcision treatment on a weekly basis may be too frequent (depending on the patient's healing period). It is best to keep sessions at least three weeks apart to help ensure sufficient recovery before the next treatment is performed. However, different doctors have different protocol so do consult your preferred doctor on his or her recommendations.
Fractional CO2 lasers are also very effective, but take note of side effects
Fractional CO2 lasers are part of a resurfacing procedure that removes layers of skin tissue in a fractionated method to help improve appearance. Fractional CO2 lasers are effective for some deep acne scars as the laser can penetrate deeper than many other lasers, generate more heat, and produce better collagen synthesis. 
However, Fractional CO2 lasers also have a higher risk of heat-related side effects such as post-inflammatory hyperpigmentation. A proper evaluation is required before the procedure. 
Fillers are great but they are not permanent
Fillers can reduce the appearance of certain types of scars and improve the texture of the skin but they are not permanent solutions and last approximately nine months to a year.
It's important to find an experienced filler injector
Lumps may develop after filler injections either due to the type of filler used, the placement, or the injection technique. It is important to find an experienced injector who knows the facial anatomy and different layers of the skin.
Treatment results are determined by various factors
Results depend on many different factors, including the number of treatment sessions and the experience of the operator. There are hundreds of settings for laser treatments as well as the manner in which the laser beams are administered. 
Isotretinoin and fractional lasers should not be applied concurrently
Isotretinoin is a good oral medication that helps decrease sebum production. However, intense lasers (such as fractional lasers) should not be used concurrently while a patient is on Isotretinoin as this can impair healing and cause further scarring. 
Before receiving acne scar treatment, it is important to know what type of scarring you have, and in what combination. Ask a trained doctor before starting any treatment plan, and understand the options available for your particular condition.