Retic changing colors

This is my 8 ft male retic that seem to be changing colors and I dont know why. His head it turning bright gold and some of his neck too and it started about a week after his first shed with me which was about 10 to 12 days ago. They aren't burns or scars and not raised up any, it kind of looks like they were painted on. I'm not sure if it tis a form of calico or not. If any one can help me out email me at CrocodileKris@msn.com. Thanks for looking.