Don't worry, if they were going to bleed to death from pipping through a vessel, they'd have probably been dead before you found it. It doesn't take much blood loss for such a tiny creature to be done in. Might be worth keeping an eye on broody momma if you're able to since she might be getting titchy with her eggs as granny hatchet mentions, unless you enlarged the hole yourself to assist.
In either case, give them 18 hours - no zip in that time, then help! Before that, try not to worry. My little guy hatched barely a half hour short of taking 18 hours from pip to zip, my anxiety over waiting certainly didn't help either of us. Best of luck to your baby!