Within The Past Week My 7-year Old Has Flaky Patches

Within the past week my 7-year old has flaky patches of skin on the crown of his head, a mild rash on his face, and a lump on the right-side of his neck. I took him to the pediatrician a few days ago and she said it is normal and nothing to worry about. She said I should change his shampoo and rub hydrocortisone cream on the rash. Tonight he now has a second lump on the left-side of his neck and the other symptoms are not any better.

What could be causing these symptoms?