Will an acne facial improve on my acne scars?

Acne Scarring: Not certain meaning of 'acne facial', but acne scarring is usually best helped with mechanical dermabrasion coupled with surface treatments (chemical or laser) to improve the depth of scarring and even out any discolorations. Deep ice pick scars are the most difficult to reduce, but each type of treatment (including some fillers on occasion) usually helps improve the appearance.

Depends on facial: Acne treatment should decrease sebum production and bacterial burden in the skin and may exfoliate as well. I'm not sure a facial treatment would really accomplish any of those things.

Not much: A facial may help a little, but not dramatically. Seek evaluation by a reputable facial plastic surgeon or dermatologist. Depending on the depth of the scars, discoloration, presence of active acne, etc there might be different treatment plans recommended. Assuming no active acne, treatment options include peels, laser treatments, dermabrasion, etc.

Perhaps : It may provide some subtle improvements.