What is going on with my babies head?

He is 4wks and 4days old he didn't have a lot of hair to begin with but he wasn't bald we have been using the shampoo from the hospital called baby phisoderm and I saw that it wasn't really clean him it was just like a cream so this time we used regular baby wash... He has dry skin but it seems like his hair is coming off with the dry skin I put lotion on him every time he gets a bath... When can I expect his hair to grow back or do you think he will lose it all... Either way just wondering...

Now...

Before...