Once I got back on the headliner, I got it almost finished up when I realized the second to last headliner bow had sunk down a bit. Turns out, tab that holds the bow had bent down, allowing the bow to drop. Son of a *****!
I ended up pealing back the headliner and making a reinforcement to prevent it from dropping again. Luckily, I was able to reinstall the headliner without a problem.