My son was/is in a similar situation. He had eczema on his face and his face had different shades from multiple things tbh..he's got allergies, eczema, scarring, melanin, air exposure etc. It's a lot for the face happening. Then its all the creams, ointments, treatments omg it was defo obvious his skin was different shades. But now he's 16 months he still has eczema but no where near as bad as when he was 5 months. His skin is coming through fine. My biggest advice and warning would be about scarring. Everything else worked out but I fear the scratch scarring might stay forever now..
I’ve known people with lighter spots on their face from eczema. With treatment, it definitely did clear up. As for me, I have eczema as well, but not on my face. However, on my face I had lighter spots due to another skin condition called pityriasis rosea. I used creams for it and it did heal and my tone evened out so you can’t see the areas I had trouble with. For me, my melanin filled back in within the year.