I have some of scar marks, mosquito bite scar marks.. what are the things can i use to change them?

Several options: In the early phrases minimizing inflammation will help to reduce post inflammatory hyperpigmentation using topical steroids. Avoidance of sun exposure may also minimize hyperpigmentation. On occasion peels and or resurfacing may help. Salicylic acid treatments may be beneficial.

Depends on skin type: It really depends on your skin type in terms of color. Fair-skinned redheads, for example may stay red and inflammed looking for months. Darker skinned inividuals will lay down a great deal of pigment that can remain forever. All of these can be treated with good combination therapy: skin creams, chemical peels, lasers, microneedling and other treatments can do wonders. See a good plastic surgeon.