Exfoliate gently 1–2 times a week
Moisturize daily with urea, lactic acid, or glycolic acid
Use sunscreen on exposed knees and elbows
Avoid harsh scrubbing and friction
Apply aloe vera or vitamin E regularly
Use a gentle retinoid at night if tolerated
Keep the skin well hydrated
Wear protective clothing to reduce rubbing
Try a brightening cream with niacinamide or kojic acid
Maintain a healthy weight if friction is a factor
Treat any underlying skin condition if present
See a dermatologist if the darkening is sudden, severe, or persistent