Can anybody tell em that how far stretch marks cream is useful??

Please tell me that is it worthwhile to use stretch marks cream on my tummy.Anybody experienced benefits from them?My obstetrician said that stretch marks during pregnanacy cant be avoided n erased by any means .so i ddnt use any cream but now i have started using that palmers cocoa er one .I have already got some stretch marks .Can they b reduced now?Was my doc true?