Open sore inside my mouth—what could it be?

So, my molar has been a lost cause for a while now, and a little chunk actually chipped off recently. I know I eventually have to head to the dentist to get it pulled since it’s beyond saving. But this morning, I woke up to this weird throbbing pain from the wisdom tooth coming in, hitting both the tooth itself and parts of my gums. While I was trying to eat breakfast, I felt this strange sensation high up on the roof of my mouth. I grabbed a mirror, took a good look, and realized there’s this tiny little hole—maybe half an inch above the tooth—on my palate that lets me see right through to that decaying molar. It feels like it just manifested overnight. Does anyone actually know how something like this happens out of nowhere, or what the fix is? Is it just going to heal itself over time?