Hi! It’s normal and it will return to normal after birth. I do use roll on deodorant (when I go out for long hours, I’m not very particular and knowledgeable on skincare so I just use what I had) and after shower I use wet wipes to rub off the dark areas. It’s not permanent so just normal cleansing will do. No need to apply aloe or any creams..
Other areas that will also darken during pregnancy are areas near, around and on your pubic area, around your nipples and belly button.