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. .......The darkening of skin can be multiple causes like tanning, vitamin B12 deficiency, addisonian pigmentation, acanthosis nigricans, lichen planus pigmentosus, rhiel's melasnosis or several other causes. A proper assessment and examination will help ascertain the proper cause. For loss of glow & dullness - there are antioxidant therapies like glutathione , lasers for rejuvenation, PRP therpy for facial rejuvenation , peels, etc. Kojic acid alone is safe but less effective. The BEST cream would depend upon the cause. Get an online consult or meet a dermatologist directly for a proper evaluation of the condition. Hope this was helpful.