u have melasma
what ur dermatologist has prescribed were right .
but it has hormonal effect also ,so u have more darkness after pregnancy
it is common that such skin become more dark after pregnancy
u need to consult dermatologist
again as u need higher treatment like
as melacare is not effective kojic acid
,arbutin ,vit c will have no effect ,so better to avoid it .
use regular sun screen and moisturizer and avoid sunlight.