Helmet - student project

Hi Helen,

Great class! I've been working on a lot of different things lately, and this concept popped up at the PERFECT time!

So while I look forward to making a skull soon, I'm working on a helmet for a freelance design. I've got it mirrored out just fine, but I'm wondering what do to if I want to make it editable in a larger file (i.e. once I put the helmet on the character I've already created). I tried exporting it, but obviously, it's just half of the image with a wonky right side. If I export it as a png, then if I try to manipulate any individual portion (the chin strap) I'm unable.