If you want to make your own head texture, download the head template from the textures section of your account. If you have photoshop, that is the program I prefer. Load the template into whatever program you're going to use, and base it around that. It get's fairly easy once you understand where everything goes.
Once you've made your head, just go back to the texture section, upload the image, and apply it. Bam, you have a new head.