Hi. Congratulations on being a new mom. The white patch that is visible is most likely Pityriasis Alba. It is a common condition in children but more common after 2-3 yrs of age. And this condition is not a cause for concern as it does not cause any issues with daily activities. But it will take a lot of time to recover. Sometimes as long as 10 years.!! But most of the times within an year or so. We have to consider and rule out other conditions also (eg- Tenia Versicolor, Vitiligo, atopic dermatitis etc)