To salvage it, I chopped off the holey bit, around the last few buttons on the bottom, cutting my favorite angled hemline, sloped down towards the back. Iron and stitch the hemline, done. New shirt!
In further refashioning this shirt, I was inspired by this lovely Honestly WTF DIY from earlier this year and the abundance of black lace I had lying around from this project. To adorn a collar with lace, simply lay a small piece along the tips however you like and glue it into place. Fold the lace around the backside of the collar, cut off excess lace, and glue again to secure. When you're happy with the positioning of the lace, stitch it down with the needle and thread (a step I have yet to complete).
The adorned collar, front and back.
The newly swingy shirt. I couldn't get a great pic of it in action, but it's been quite a wardrobe workhorse so far, good paired with high-waisted bottoms and peeking out from crewneck sweaters.