Re: HELP!! What is this??
It sounds like it might be a clogged duct. I've had them. Try nursing that side first for a while, so there's more vigorous sucking to help it unclog. Usually, it clears within a couple of days.
Linda -- proud mom of Rachel (20), Joshua (15), Elisheva (7), and Moshe (3), and 2 wonderful grown stepdaughters.