Hi,
Pigmentation after psoriasis flares is termed post-inflammatory hyperpigmentation (PIH) and managed as such.
Management of PIH follows the following strategies:
1. Control the causative skin disease well.
2. Moisturize frequently
3. Avoid aggravating factors such as UV exposure, scratching, picking on skin
The PIH will gradually fade over several months once the skin inflammation is fully controlled and removed.
The above procedures that you have listed play little, if any, role in treatment.
Hope this helps!