How long do brown pimple marks last?

A brown mark remained where the pimple had subsided.

I would like to know how long it usually takes for these brown marks to fade naturally. . If it remains the same after a few months, a laser at the dermatology clinic , I wonder if you are receiving treatment like whitening care. , I am wondering if it is okay to just apply the product and observe it. .

For those of you who have visited a dermatologist because of brown marks, what kind of treatment did you receive and how did your condition improve? ?