Unfortunately there is no so called single permanent treatment for pigmentation problems.If any identifiable cause is found like Vit
B12 deficiency,Iron Deficiency,Atopy,Or Photocontact Pigmentation the treatment of the specific cause helps.
Next Steps
Use of sunscreens on regular basis and avoiding cosmetic overuse along with tyrosinase inhibitors creams at night might help.
Health Tips
Consult your dermatologist and follow treatment