Possible TMI Nipple related

So I’m just over 20 weeks pregnant and this is my first pregnancy. I noticed today that tiny white spots were on my nipples and some of the spots would even rub off of my nipples. They became more noticeable while I was in the shower. I looked it up online but all I could find was info about Montgomery glands but those from what I read are around the nipples and not directly on them. Has anyone experienced this or know what it could be? I’m curious if it is a sign I might start lactating soon.