Wtf? I don't even get how that could happen.
Pretty awesome cut.
You need GOOD stitches buddy. Don't just butterfly that sh*t... You'll scar and it'll open up easier in the future.
Also, remember you only have a finite window to get stitches. Most cases I believe it's about 24hrs. After that the doc won't want to stitch it anymore.
I'm kind of wishing I would have got stitches now but I didn't. It's healing pretty well on it's own. I'm taking care to clean it a couple times a day with hydrogen peroxide, iodine and antibacterial ointment.