Hello, I would be happy to help you with your question.
While this sounds like a clogged duct, like your doctor had previously supposed, the other possibility (given its re-occurrence in the same location and significant pain) is a recurrent herpes blister
. This most definitely needs to be checked out within the next 24 hours and a herpes culture done on the fluid within the cyst
. Active herpes at the time of a delivery is dangerous for your fetus. At this point, if this is what it is, it can be treated and suppressed so that risk of harm is minimal to none.
I hope that this helps and good luck!