Hip dips do not usually “come back” because of air or because the area has no circulation. They are often an anatomic contour related to the pelvis, greater trochanter, muscle/tendon attachments, and fat distribution. With a BBL or hip dip fat transfer, some of the transferred fat commonly resorbs in the first few months, so the early fullness may decrease. The fat that survives after healing can be long-lasting, but it can still change with weight gain or loss. The hip dip area can be harder to fill than the central buttock because the tissues may be tight and there is a limited safe capacity for fat placement. Whether it is worth it depends on your anatomy, donor fat, skin quality, and how much correction you expect. A smoother lateral hip transition is often more realistic than a perfectly round, no-dip shape, and some patients need more than one session. Safety is essential: fat should be placed only in the subcutaneous layer, not into the gluteal muscle, and overly aggressive filling is not worth the risk.