There are various causes of dark circles.
Dark circles can appear temporarily due to temporary fatigue or facial swelling, but in most cases, they are caused by problems with the fat pads under the eyes.
The most common type of dark circle is when the under-eye fat protrudes slightly and forms a boundary with the sunken tear trough.

Cause of under-eye dark circles. A real model with consent for release.
The reason the tear trough looks sunken under the eyes is due to a firm structure called the tear trough ligament. This strong ligament is firmly attached to the bony area beneath the eyes.

The under-eye fat pads and the tear trough ligament
Because of the structure under the eyes, when the under-eye fat pads become loose, the under-eye fat protrudes forward, making the sunken tear trough area appear more prominent.
And when the under-eye fat pads become loose, they compress the orbicularis oculi muscle in front of them, and as a result, the compressed orbicularis oculi muscle shows through the thin skin, creating dark circles that make the under-eye area appear darker.

The orbicularis oculi muscle visible through the skin due to pressure from under-eye fat
Although various procedures have been introduced to address under-eye dark circles, under-eye fat repositioning is the best solution for addressing the root cause of dark circles.
Under-eye fat repositioning is performed through a small incision in the conjunctival area inside the eye, so there is no external incision and no stitches.

Surgical method of under-eye fat repositioning
Under-eye fat repositioning is a surgical method in which the sunken tear trough under the eyes is carefully dissected, then the loosened under-eye fat pads are thoroughly released, moved downward, and firmly fixed in place.
When performed in this way, under-eye fat repositioning relieves the pressure on the orbicularis oculi muscle caused by the bulging fat pads under the eyes, improving the dark under-eye circles. The sunken area of the tear trough is filled by the repositioned fat, which has the advantage of producing long-lasting results.
In addition, because under-eye fat repositioning is performed through a small incision in the conjunctiva, recovery is fast.
Usually, skin-colored tape is applied after surgery to stabilize the under-eye area, and it can be removed 3 to 4 days after the procedure.
And because there are no stitches, no additional treatment or stitch removal is necessary.

1 week after revision nose surgery and under-eye fat repositioning
The recovery period after under-eye fat repositioning can be considered to be about 3 days, since there is no stitch removal required and you can return to daily life immediately after removing the tape.
Even when under-eye fat repositioning is performed together with other cosmetic procedures such as rhinoplasty, the recovery period does not become longer, and because it is a surgery that addresses the fundamental cause of under-eye dark circles, the effects can last for a long time.

A real model with consent for release.