Hello and welcome to the forums,
I don't see any worm on his head; I do see a few pin feathers, is he moulting right now? Sometimes the discoloration can be due to moulting but I can't really see well in the photos. Do you have additional photos of the area that are more in-focus?
Meanwhile, you've come to a great place to learn even more about the best of budgie care practices. Please be sure to read through the forums' many budgie articles and "stickies" to ensure you're up to date on everything! If you have any questions after doing so, please do ask as we'd love to help.
Please keep us updated on your little one's condition!!
Best wishes
