Sunken acne scars are also known as atrophic acne scars. These are shown to benefit from two main types of procedures:
1. Skin resurfacing (microneedling, fractional radiofrequency, various fractional lasers)
2. Subcision with or without fillers and biostimulators
I would suggest a proper assessment by an experienced doctor who is familiar with all these options, especially if you have never been offered them before. Sometimes, a single session of subcision can help more than multiple sessions of skin resurfacing, and hence be much more cost-saving. There are also various fractional lasers that have different effects for different scar types.
I agree with Dr Justin that fractional radiofrequency can definitely help more than microneedling (even with good stem cell serums), and I own a fractional radiofrequency device at my clinic too. However, this device may not be suitable for all scars. It is useful for rolling scars, and other devices are still required for different scar types. Fractional microneedling also break the top layer of the skin and can cause increased downtime if used to deep depths, higher risk of infection/acne and also increased sensitivity initially (just like lasers).
If you have deep rolling or box scars, fractional non-ablative lasers like the erbium-glass laser are a proven better option than fractional radiofrequency according to this study (Comparative study on efficacy and safety of 1550 nm Er:Glass fractional laser and fractional radiofrequency microneedle device for facial atrophic acne scar.) A proper assessment is still crucial before any treatment.
It is a misconception that lasers make the skin thinner and more sensitive. If done appropriately and with proper rest intervals, lasers increase the thickness of the skin and can even decrease skin sensitivity. Similar to fractional radiofrequency and microneedling, the skin can be more sensitive during the initial healing phase, so proper post-care is also important.
