demelan peel does not improve shades by 2 times in single sitting.... Unless the various shades of colour matching that they have are very similar to each other. When you mention about the scars do you mean the dark marks OR the depressions in the skin surface which occur when big acne pimples heal. For the treatment of the pigmentation marks creams can be used. For the treatment of the depressed scars procedures are required to get an improvement. There are options like hyaluronic acid filler or subdermal fat transplant which can be done for the holes if they are slightly bigger. But the very tiny depressed scars would require either laser treatment or micro needling. For the black marks you can try applying kojic cream for a month which will decrease the pigmentation on the marks. But for the holes some kind of procedural intervention definitely be needed. There are multiple causes for facial hyperpigmentation. Sun tan, overweight, pigmentation disorders like acanthosis nigricans or melasma, lichen planus pigmentosus, rhiel's melasnosis, nutritional deficiency etc are some conditions. Unless someone examines you, we cannot know the cause. Unless we find out the cause it is difficult and pointless to treat. Get an online consult or meet a dermatologist directly for a proper evaluation of the condition. Hope this was helpful.