20 days PO. How to treat chemical peel burn? Can it be treated now? (photo)

Thank you for your question and posting pictures.  It looks and sounds like you might have Post Inflammatory Hyperpigmentation (PIH).  You can start by looking for prescription strength 4% Hydroquinone (HQ) to reduce the pigment.  Do not buy it over the counter or off the internet.  Laws vary by state.  In Texas, physicians can prescribe and dispense in office.  We have been very successful using the PicoSure laser with the FOCUS and / or Flat Lenses eliminating hyperpigmentation with a series of treatments.  
FOCUS lens treatments have the extra benefit of reducing the underlying scar tissue.  This is one of our go to treatments for patients older than 40 and worried about the signs of aging.  This laser is safe for all skin types.  Start with sunscreen every day!  Once you have treated your hyperpigmentation to your satisfaction, you will probably need a follow treatment every 6 to 12 months depending your level of re-pigmentation.  Best of luck.

Thank you for your question and photograph. It's difficult to evaluate your skin through this type of forum, but from what I can see, it looks like you have post-inflammatory hyperpigmentation (dark marks). In some cases, the discoloration may fade over time but that can take months to over a year to achieve. Hyperpigmentation can be treated with topical lightening creams or laser treatments. However, each option comes with their own side effects and risks.  I highly recommend you consult with a board certified dermatologist or plastic surgeon to discuss treatment options that best suit your needs. Take care and good luck.