Are they small kind of a spongy mass that is under the nipple, slightly protruding under the nipple and they raise up kind of like a zit when the nipple is erect?

EricaB posted this very helpful link earlier: http://www.breastnotes.com/aware/aware-stages-opt.html I think the answer to your question is yes, but I'm not sure, because I had mine 20 years ago and didn't pay too much attention at the time.

Dog gone it, Malina. You stole my thunder, but I thank you for the attribution.

I think this is yet another case of everyone is different. When I saw the thread title, before reading anything, my first thought was, "They don't LOOK like anything, but you can feel them", because that's how it was for me - nothing to actually see when I looked in the mirror but a firm, rather tender lump, which could be felt behind the nipple.