What to Expect When Your Breasts Bud. YOUTH. When breasts buds form, some girls worry that the knot or lump under the nipple is a sign of breast cancer. Breasts and Bras. KidsHealth Budding — like a flower has buds. A breast bud is like a small raised bump behind the nipple. After breast budding happens. Girls born with this have no breast buds, make the problem worse or cause damage to the internal tissues. Rare breast about problems with breast.