Without a photo I cannot be certain but it just sounds like roots trying to form above your soil level. It’s very common and means you have above average root growth. (That’s awesome!!!) my advice is, if you have room in the pot, fill soil up higher on stem to cover the bumps.
“White†sounds like roots
“towards the bottom of stem†screams roots
and “healthy plant growth†all push me towards root growth.
a photo will confirm.
if it is roots you can do absolutely nothing and the plant will self prune those roots so they’ll never grow, but I’d personally (since you say they’re a week from flower) transplant to bigger pots and fill media higher on stem a day or two before making the switch. Allow that explosive root growth to continue!
I personally transplant day of the switch into larger pots.