Hey - love the username. When the jaw won't close, it's often what's called "open lock," which is due to the condyle not being able to translate back into the groove with the mandibular fossa because the TMJ disc is stuck posterior (behind it) - looking at some online images should hopefully help this make sense visually.

A PT (with TMJ expertise) or regular dentist may be able to help figure out what's going on. Some people will go to urgent or ER care because they're having trouble eating or breathing, and I believe the goal is to reduce the condyle back into the joint socket.

Anyway, I don't know for sure what's going on, but that's one possibility to consider if you can't close your jaw, especially if it was acute (happened suddenly).