What your son has is called eczema. In case you do not know what eczema is, it is dry patches of skin that most times is very itchy. But I have noticed on that spot, my children most times do not itch. Both my children have it. Sometimes they can grow out of it. There is a great product you can buy over-the-counter called aquaphor. It has a similar consistancy as vasaline. Or just using vasaline can work as well. If that doesn't help, take him in to the Dr. He/she can prescribe something like elidel. Hope this helps.