I used 10% glycolic acid on my dark neck and now the skin is burning and looks darker.

Applying 10% glycolic acid to the delicate skin of the neck can compromise the skin barrier, triggering severe inflammation and a paradoxical darkening known as Post-Inflammatory Hyperpigmentation (PIH). Because glycolic acid has the smallest molecular weight of all alpha-hydroxy acids (AHAs), a 10% concentration penetrates rapidly, overwhelming the thin epidermal tissue of the neck. This chemical burn activates the enzyme tyrosinase, which transforms the amino acid tyrosine into excess melanin pigments, making the area darker.

The initial localized darkening on your neck, while your chest remained fair, is likely not a sun tan but a physiological condition called Acanthosis Nigricans. Dr. Divya Sharma, MBBS, MD Skin, Dermatologist, states that Acanthosis Nigricans causes the skin to turn dark and velvety around the neck and is strongly linked to high blood insulin levels, often seen in conditions like Polycystic Ovary Syndrome (PCOS).

Indian skin types (Fitzpatrick III-V) are highly prone to this hyper-reactivity. Clinical studies show that over 80% of the Indian population presents skin color heterogeneity, meaning any friction or chemical irritation quickly leads to localized hyperpigmentation. When the 10% glycolic acid burned your skin, it triggered an inflammatory cascade that worsened the existing melanin overproduction.

Clinical Recovery Protocol

• Phase 1: Barrier Repair (Days 1-14): Immediately halt the 10% glycolic acid. Apply a barrier-repairing moisturizer containing ceramides and hyaluronic acid twice daily to neutralize the burning reaction and rebuild the compromised epidermis.
• Phase 2: Gentle Tyrosinase Inhibition (Weeks 3-8): Once the skin has completely healed, switch to non-exfoliating pigment correctors. Dr. Harish Koutam, Chief Dermatologist, recommends azelaic acid and niacinamide to safely block melanin synthesis. Niacinamide stops melanosome transfer from melanocytes to keratinocytes without causing chemical burns. A targeted treatment like the 10% Niacinamide Face Serum can help regulate this pigmentation.
• Phase 3: Systemic Evaluation: Because Acanthosis Nigricans is driven by internal metabolic factors, topical skincare alone cannot permanently resolve it. Consult a physician to evaluate fasting insulin levels and address the root cause.