Dark areas after an infection or inflammation is called post inflammatory hyper pigmentation (PIH). In most cases the dark areas lighten spontaneously over a period of time but some chemicals can hasten this process.
Hydroquonone is one of these chemicals which is very efficient to improve dark areas. "Eukroma Skin Lightening cream" is one of the product in the market.
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Next Steps
She has to apply it on the dark areas for 2 times per day for at least 4-6 weeks or until dark areas disappear.
Health Tips
Some times it takes few months for complete resolution.