Ouch! It happens now & then, mostly with snakes that have longer teeth. I'd bet it's a loose tooth (or maybe it is by now). It's been years since I had a snake do this -thankfully.
First I'd try to uncurl her lip- gently but firmly with some implement that's tiny enough & reasonably safe to get in behind it to un-latch her curled lip. This has worked for me.
Other option- if you can see the tooth sticking out & can grab it with small pliers, pull it straight out & then dab some antiseptic (Vetericyn or Betadine) on the tiny wound- it should heal up okay.
Or, go the the vet & let them decide if you don't feel up to either option. One thing is for certain- you cannot leave her like this.
(This is why snakes often yawn before or after they eat- to get all their pesky teeth back in alignment.)