Hyperpigmentation on forehead.

My forehead has a black patch hyperpigmentation and I tried everything but it's not going.its has happened since my pregnancy.I have taken 3 chemical peel and 3laser session from kaya.no effect I am trying home remedies lemon juice..besan..rice flour.potato and tomato ice cubes..no effect. I have used the ordinary glycolic toner and the aha bha peeling solution but it also didn't removed the black patch. After consulting dermatologist Now I m using metalite 15 and glyco 12 cream on alternate nights .Before that I m using aquasoft fc moisturizer. It's been 2weeks I m using.still no effect. Please help me in getting rid of this hyperpigmentation. Shall I continue use Metalite 15 and glyco 12.Will it really help in removing the hyperpigmentation permanently