White discoloration on my breast?

I noticed months and months ago, a pimple on my right breast, extremely sore and it be weepy. It was more or less the size of a normal zit, but I hold never gotten one there up to that time.
Now its this white discoloration it does protrud like a pimple but it doesn't hurt. What could this be?
I am 30 weeks pregnant, and the pimple be there previously I got pregnant, it stay a scratchy pimple for a week or so, and I did notice the white discoloration awhile ago, a moment ago noticed again that its still nearby. YOU SHOULD BRING THIS UP TO YOUR DR AT YOUR NEXT APPT..