i have tried almost everything,

prescription ones and non-prescription ones, including Vc. please read:

http://bbs.wenxuecity.com/health/383710.html

you can try this:

银耳富有天然植物性胶质，加上它的滋阴作用，长期服用可以润肤，并有祛除脸部黄褐斑、雀斑的功效；
http://bbs.wenxuecity.com/health/397856.html

do you use 避孕药或避孕环吗？if yes, stop it. they may cause this problem - disturb  your hormone.