Had something similar a couple of weeks ago. Mine was on the areola right next to almost on the nipple.
I rang the ABA and they said it sounded like white spot. I massaged and massaged and it didn't seem to get better nor did anything come out of it. I went to the GP and he didn't know what white spot was and gave me a script for AB's after googling the ABA site and white spot didn't come up. Not sure if it was coincidence or what it was, it started to get better a day or so into the AB's. I hesitated taking the AB's and rang the medicine hotline to check to make sure it was ok and wouldn't interfere with BF.
May be worth seeing a lactation consultant if you can to see if they can have a look.