The worse the initial injury, the worse the scar will be.
Scars form when the dermal skin layer is damaged. That can be by a trauma, surgery, or acne for example. The skin heals and in doing so, forms new collagen fibres to repair the damage. This results in a scar. The new scar tissue has a different property and texture, and sometimes colour, than the surrounding tissue.
Scarring can be improved with a variety of treatment modalities. Fractional radio frequency, LED therapy and micro needling with RF can all have a good result.
Your practitioner will consult you before treatment taking a history of health and skin, and probably photograph the area. In Micro-needling, or Micro-needling with RF treatments, they will wear gloves and the area will be thoroughly cleaned prior to treatment and after treatment the area is covered in antiseptic cream. You will use a topical anaesthetic cream prior to treatment starting. As LED is a non invasive treatment, those precautions are not necessary.