I have brown spots on my back & chest due to acne. what can get rid of them? ive had them all my life. went 2 derm & gave me trentinoin, doesnt work!

Not treatable: Some of the spots are probably due to acne while others are probably solar lentigos. The acne marks fade after several months; the others are permanent. Watch your skin for signs of melanoma. If you still have acne, manage it. Use a sunscreen. Many of my students, make and female, have these spots; no one minds; they are relics of a vigorous youth.