Acne scars are a problem immediately after having breakouts and can continue to persist even years later! The key to understanding your options for improving the appearance or actively treating them is to first figure out what kind of scars you have.
The most common would be discoloration or redness. This is known as post inflammatory hyperpigmentation or post inflammatory erythema. The way you can tell if you are in this category is if you look in the mirror and can see exactly where your breakouts were, but touching your skin reveals that it is remarkably smooth. When you run your fingers over your face with your eyes closed there are no bumps or irregularities.
This type of pigment or redness will tend to fade with time alone but can be helped with a few steps. The first is wearing a daily sunscreen with an spf of 30 or more. This will prevent the sun from keeping the excess pigment around. The second is to consider adding in a topical to help fade these areas. I’m not a fan of true bleaching creams containing hydroquinone for acne scars as they are not able to always distinguish between normal skin and discoloration. It helps to use products that contain azaleic acid, retinol, or kojic acid daily for 6-8 weeks to fade.
If you look in the mirror and see raised acne scars that are no longer active acne, then a topical may have trouble alone bringing these down. This type of scarring is best handled with your dermatologist by resurfacing the skin to improve the overall appearance.
If you see pitted acne scars or sloping acne scars that look like dells or depressions in the skin, think of these as missing substance underneath that made them pucker into the skin. For this, topical agents containing retinol or Hyaluronic Acid may improve the appearance by adding some turgor to the skin, they will not necessarily lead to long term improvement.
These are best handled by your dermatologist and may need a combination of approaches that could include resurfacing lasers, microneedling, subcision, fillers, and - for really tough scars- excision.