Labiaplasty is a plastic surgery procedure that reduces the size of the inner lips of the vulva (labia minora) so that they are smaller than the outer lips (labia majora). But what actually happens during this process?

Before

Meet with your plastic surgeon for a consultation.
See your family doctor to make sure you are healthy enough to have surgery. This might mean having blood work done or an EKG depending on your age and your medical history.
Book your surgery once you have been medically cleared.
At least 6 weeks before: Quit smoking.
10 days before: Avoid taking aspirin, ibuprofen or any other medication or herbal supplement that might increase the risk of bleeding or bruising.
1 day before: Take any prescribed antibiotics.
The morning of: Shower and completely shave the pubic area.

During

You will be given a general anesthetic to “knock you out” just prior to the procedure, as well as a local anesthetic to numb the area during (and for a few hours after) surgery.
Your surgeon will mark to area to be removed.
The exact procedure you will undergo depends on the surgeon and your individual needs. There are three options:

Amputation

Amputation is the original (and most simplistic) method as the surgeon basically cuts the labia minora down to a smaller size with either a scalpel or a laser. If a scalpel was used, the surgeon will then stitch the edge. The main drawback of this technique is that the natural edge of the labia is replaced by a scar, creating an unnatural appearance. There is also a high risk of nerve damage.1-7

Central Wedge Resection

Using this technique, the natural edge remains enacted because a “wedge” of excess tissue is removed from the middle of the labia.2 Once again, though, because an entire chunk of flesh is being removed, nerve connections can be damaged, which can lead to post-operative numbness.

De-epithelialization

De-epithelialization also removes excess tissue from the middle of the labia. However, unlike central wedge resection, de-epithelialization removes the epithelial (or outer-most) layers of tissue on both sides of the labia, rather than all of it.5 As a result, this technique preserves the edge of the labia as well as most of the sensitive nerve endings found throughout the entire structure. Tissue removal can be done with either a scalpel or a laser. The laser causes less bleeding but has been reported to cause epidermal cysts.

After

You will generally need 3-4 days at home to recover.
Take Tylenol or the pain medication prescribed by your plastic surgeon to relieve your pain/discomfort. DO NOT take aspirin or ibuprofen because they can increase bruising and bleeding.
Shower the day after surgery.
Clean the incision site with hydrogen peroxide and put antibiotic cream/ointment on daily.
Your stitches should dissolve within 2-2 ½ weeks.
Swelling and tenderness should disappear within 6 weeks.
It will take between 6 months to a year before you will see the absolute final results.

References:

Hodgkinson DJ, Hait G. Aesthetic vaginal labioplasty. Plast Reconstr Surg. 1984;74(3):414-416.
Alter GJ. A new technique for aesthetic labia minora reduction. Ann Plast Surg. 1998;40(3):287-290.
Alter GJ. Central wedge nymphectomy with a 90-degree Z-plasty for aesthetic reduction of the labia minora. Plast Reconstr Surg. 2005;115(7):2144-2145.
Rouzier R, Louis-Sylvestre C, Paniel BJ, Haddad B. Hypertrophy of labia minora: experience with 163 reductions. Am J Obstet Gynecol. 2000;182(1 Pt 1):35-40.
Choi HY, Kim KT. A new method for aesthetic reduction of labia minora (the deepithelialized reduction of labioplasty). Plast Reconstr Surg. 2000;105(1):419-422.
Munhoz AM, Filassi JR, Ricci MD, Aldrighi C, Correia LD, Aldrighi JM, et al. Aesthetic labia minora reduction with inferior wedge resection and superior pedicle flap reconstruction. Plast Reconstr Surg. 2006;118(5):1237-1250.
Maas SM, Hage JJ. Functional and aesthetic labia minora reduction. Plast Reconstr Surg. 2000;105(4):1453-1456.