Indent on back of baby's skull

Has anyone experienced this? My LO has a slight indent on the back of her skull. It doesn't go too deep but it's about the size of a quarter. I noticed it when she was maybe only a couple weeks old. I asked her pediatrician right when I noticed it and he said it's just the way her skull formed and it will work its way out eventually. I asked him again at her 4 month appointment and he said not to worry about it and gave me the same run around. Has anyone experienced this with their LO? Did it work itself out like my LO's pediatrician says it will? I can't post a picture of it because she has so much hair you can't see it (only feel it). I guess I am just afraid it may cause developmental or neurological issues in the future.