To treat internally the cause of pigmentation, do this pranayam daily.This will give you a glowing face in a few months. The benefit is gradual, so be patient.
Build up your timing gradually.If you feel tired or dizzy, stop and resume after one minute.
Kapalbhati pranayam -(Do it before eating) Push air forcefully out through the nose about once per second. Stomach will itself go in(contract in). The breathing in(through the nose) will happen automatically. Establish a rhythm and do for 20 to 30 minutes twice a day. Children under 15 years – do 5 to 10 minutes twice a day.
Not for pregnant women. Seriously ill people do it gently.
There are two causes for pigmentation problems I know of -- melanin problems and liver problems. It's unlikely anything topical would completely take care of the problem without also tending to the internal cause, and exfoliating just takes off dead skin, it doesn't do anything about pigmentation, the cause of which is presumably under the outer layer of the skin.