Pressure, like leaning on a desk
Friction, from scarves or jewelry
Insulin resistance in an overweight person
Post inflammation excitation of pigment cells, like following a rash from creams or perfumes
Contact with psoralen from limes, lemons
Excess sun in those areas
Make sure acne is in control. Flat, pink/red/purple areas can be lasered to help normalize color. Dented areas can be leveled with filler. Tiny “ice pick” scars can be ameliorated with fractionated laser. Really significant scarring can be treated with dermabrasion.
So, yes, there are many things to do to help acne scarring.
Cole Fulwider, MD