Skin Anatomy, Physiology, and Healing
Skin anatomy, physiology, and healing questions test whether you can place pigment at the correct depth, predict healing, and recognize when skin condition changes the plan. Permanent makeup creates a controlled wound: the needle disrupts the epidermis and upper dermis, and the body's response determines retention, fading, and complications.
Layers and depth
The epidermis is avascular and renews roughly every 28 days in young adults, more slowly with age. The dermis contains collagen, elastin, fibroblasts, blood vessels, nerves, and appendages. The hypodermis is subcutaneous fat. PMU pigment belongs in the papillary dermis: superficial enough to be visible, deep enough to avoid rapid epidermal shedding. Too shallow and pigment sits in the epidermis and flakes away; too deep and trauma to the reticular dermis and vessels causes blurring, blowout, or scarring.
Healing phases
Hemostasis occurs within minutes, inflammation over days 1-3, proliferation over days 3-21, and remodeling over weeks to months. Expect oozing, swelling, and tenderness, then flaking around days 3-7 for brows; lips may swell more. Pigment looks darker and warmer immediately because of blood and lymph, then lightens an estimated 20-40% during healing.
Worked example
A client asks why her brows look patchy at day 10. Reasoning: epidermal flaking and phagocytosis are still active, so patchiness is normal before the 4-6 week touch-up window. Do not schedule an early second pass before healing stabilizes.
Traps
Assuming pigment stays exactly where it is placed forever; confusing dermis with hypodermis; treating every Fitzpatrick type as identical; ignoring medications or conditions that slow healing.