How long does it take for hyperpigmentation to go away after inflammation?

Post-inflammatory hyperpigmentation in general can gradually fade or even disappear over time.
Most begin to fade in about 3 months, with a few individual longer ones reaching about 2 years. During this time, patients can take vitamin C, vitamin E, tranexamic acid and other medications to help the pigmentation fade. Take care of strict sun protection to avoid local inflammatory reactions.