There are 2 types of post acne spots.
Flat pink/reddish spots: These spots are caused by enlargement of microscopic capillaries. Fortunately, pink spots will usually fade without special treatment in a few weeks after your active Acne is over.
Flat brown spots: As brown will get darker in the sun, need you avoid the sun and use a sunscreen on a regular basis. Some of these spots will fade by themselves and some will need further treatment. Treatment for brown spots should start with OTC whitening creams and continue if needed with stronger prescription whitening creams or superficial chemical peels.
Persistent pink and brown spots can be also treated with light sources, called Intense Pulse light (IPL). These IPL’s produce intense pulses of light very similar to camera flash. The light is absorbed in small capillaries and the melanin globules in the spots causing them to fade.
Regarding "real scars" in which the skin is depressed (like a hole or valley) there is a need for a Dermatologist treatment - best with microneedle RF. 🙂