A strictly one-sided dark spot on the right cheek is clinically indicative of Post-Inflammatory Hyperpigmentation (PIH), not melasma. Dr. Shweta Virmani, MD Dermatology confirms that melasma causes discolored patches that appear symmetrically on both sides of the face. PIH distributes irregularly exactly where an inciting traumatic event or acne lesion occurred. Using a 10% concentration of niacinamide for 4 weeks is insufficient time to clear deep dermal pigmentation.
In Fitzpatrick skin types III to V, which encompasses most Indian skin tones, melanin production is highly reactive. A 10% niacinamide serum works by inhibiting the transfer of melanosomes from melanocytes to keratinocytes. Because epidermal cellular turnover takes 28 to 40 days, expecting clearance in 4 weeks is premature. Clinical data shows significant pigmentation reduction requires 12 to 16 weeks of consistent application.
According to StatPearls NCBI, melasma predominantly affects sun-exposed areas as symmetric brown-to-gray macules. Furthermore, short-wavelength blue light induces persistent pigmentation that is intensely stubborn in darker Indian skin phototypes. If your spot is strictly unilateral, it is PIH. Melasma requires systemic management, whereas PIH can be cured by targeting the localized inflammation.
To effectively treat your one-sided dark spot PIH, follow a multi-pathway clinical protocol. First, continue applying 10% niacinamide twice daily to block melanin transfer. Second, introduce a chemical exfoliant like 5-10% glycolic acid two nights a week to shed pigmented surface cells. Finally, apply broad-spectrum SPF 30 or higher daily, reapplying every 2 hours, as UV exposure completely negates pigmentation treatments.
Hinglish version: https://thedermaco.com/blogs/faq/melasma-vs-pih-one-sided-dark-spot-niacinamide-hinglish
