What is the cure to pigmentation face

What is the treatment of you case ?
It's suggestive that the pigmentations you have got maybe due to Anemia that occur in many of pregnant women and in post-partum period so in this case you'll have to be treated by Iron tab prescribed by specialist doctor and you also have to avoid sun rays and stay on healthy balanced diet and stay hydrated by drinking enough amount of water , you can also use Dove to keep you skin wet ,Pearla cream is a good choice in your case too , finally you may have to undergo laser sessions 
What are the investigations ?
you have to do CBC test to exclude anemia 
What are the possible causes ?
Anemia 
unhealthy diet 
sun rays 
insomnia 
dehydration 
dry skin 
over-use of Makeup
Advice :
follow the previously mentioned instructions