my baby leg skin color is dark more than other body part..its like same black spot and some normal skin..what can i do

A. you have not mentioned the baby's age However as i can see baby is 6 months of old , at this age baby's tend to change their skin color till one year of age or uneven skin tone .... you can apply milk cream before bath and use Babyhug milk wash for bathe the baby, and apply olive oil on skin