So my son has those 3 little white spots on his gums right there and you can even see one in the…

So my son has those 3 little white spots on his gums right there and you can even see one in the back; they've pretty much been there since birth. His dr said they were "Epstein pearls" at his 2 day check up and hasn't said anything since about them, but from what I've read they are usually gone by 3 months. My son is 7 months. Any ideas? Or have a child that had them longer than 3 months?