Nipple Scabbing? ***TMI****

FTM, this is my first pregnancy and I notice my nipples are dry and have a crusty like scabby layer. I have included pictures . So just a minute ago I was scratching my boobs, and a slight piece of skin came up on my nippie. I was able to pick it right off,it kinda of weirded me out. It didn't hurt and some parts of the scab  s dark, perhaps my melanin and the rest is dirty yellow type color. Doesn't hurt but I kept picking at it because I was curious to see what it is. Never have I experienced this before, what could it be? Pictures Included, does this usually happen during pregnancy? Im 22wks with my first child. Any suggestions on how to take care of this? I really would appreciate some insights and help on this. Thanks in advance!