Go to Ebay. You will probably find a new end mill for cheaper than trying to fix this one. It may take a week or two to find the exact one you need.
Any time I need a mill that is an expensive size and may only be used once, Ebay is where I look.
I bought a new Kyocera 3/4" solid carbide end mill six months ago for $17. It took weeks looking to find one this cheap but was worth the wait.
Thanks for the advice. I try to get all my milling tools off ebay as well because of the great prices. I got this Niagara 3/4" shank 1" cut diameter hss end mill for $12. I will be looking out for a similar one. But in the meantime I'll probably experiment with the chipped corner as regardless of what I mess with down there it'll still make a good roughing cutter.