What is the best way to get rid of this scar from a face scratch? (Photo)

I would treat this scar with a combination of pulsed dye laser, thulium fractional laser, fractional erbium laser, and topical skin modulation. Moisturize the skin with a ceramide cream (Elevase) or similar treatment.

Best,
Dr, Karamanoukian
Realself100 Surgeon

First, let me say that I am not surprised at all at the failure of the laser gizmos. Unfortunately, the hard science to support the use of these expensive "bells and whistles" devices lags well behind the heavy marketing and social media buzz that surrounds them.
At least from the photo provided, it appears that the scar is Indented and somewhat Hypopigmented. If so, then Subcision, which I have been routinely performing since 1995, can be used to elevate and smooth the scar and Dermastamp manual microneedling (no need for the added expense and risks of RF microneedling gizmos) can be performed to better blend any residual, superficial color and texture irregularities with the surrounding normal skin. You would be wise to consult an experienced, board certified cosmetic dermatologist and best of luck.