Hi Dr...im 24 Years Old...and I Gave Birth To A

hi dr...im 24 years old...and i gave birth to a baby boy 11 months ago and started with all the skin problems from then,i had pigmentation around my nose and neck ,on consulting a skin specialist ,he asked me to use the cream melano-tx. now thats way ok but its still there..now suddenly i have developed a lot of itching around my hands ,arms, back and neck.its becoming lighttly inflamatory with white patches around my hands.can i know whats the reason for it?and regarding my skin texture also i have lost a lot of colour..im becoming dark day by day ?what is the reason for it ?im taking vitamin d suppliments does it has to do anything with the skin?