When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Maybe you can get the plug out this way. Take a spark plug socket and extension if necessary, get it lined up on the flats as best you can then beat it on with a hammer. It will deform the metal from the heat shield as you drive it on.
That's what I would do before tearing that head off... You are asking for more problems unless you are planning to rebuild, if not you still need new head bolts, and a new gasket.