Pimple looking mass on nipple

It's been about 6 months now that I've had a growth on my left nipple. It grows to be about a pea size with white and bloody discharge that pops on its own, then days later the mass forms again. I told my dr about it and he said it was just a gland or duct that is clogged, but I'm getting worried that it keeps coming back over and over again in the exact same spot. I don't feel like this is normal at all 😕 Help someone!!