Do the white patches (hypopigmentation) that follow an eczema outbreak usually go away?

With time. With time (usually months), the lighter patches should gradually improve. Make sure to moisturize regularly with a hypoallergenic frangrance-free product.
Pigmentationissues. It is relatively common for newly healing skin to be under pigmented compared to the surrounding skin. This occurs because the activity of the pigment producing melanocytes is one of the last cellular systems to resume normal activity.Many tomes it can take a year or so th resume normal activity.