How safe is the Erbium laser and what are the long term risks? I.e. scarring, hyperpigmentation, etc

Thank you for your question. Hyperpigmentation from any type needs a combination approach of peels like cosmelan, lasers like clear and brilliant and aerolase or laser genesis, radiofrequency like venus viva, and constant skin care and sun protection. Bimontly facials with silk peel dermalinfusion is essential to hydrate, exfoliate and infuse vitamins and antioxidants into the skin. If you have acne you can do additional treatments and peels to get more improvement. I recommend getting a formal evaluation with a cosmestic dermatologist. Best, Dr. Emer

thanks for posting. 
as with any ablative laser, there is a risk of hyperpigmentation, reddness, swelling and scarring. 
The other suggestion is that if your scars are atrophic or think shallow scars you could consider bellafill injections with subcisions and perhaps a bit of TCA peel as well prior to treatment. 
Best Wishes