After hitting a villager accidentally, his prices rose drastically. I cannot swap for a new villager as it is the only villager I have. How long do I need to wait/what do I need to do in order for its trades to revert back to their original prices? The version is 1.16 pre release 2. Anything helps!
I think that doing a lot of trading will cause them to, gradually, lower their prices.
Also, if I understand the Wiki correctly, popularity is stored per village, not per villager so destroying all the beds and bells in the area (after locking in the villager so he doesn't run away) and then replacing them after a day or so might help.
If you get the villager zombiefied and then cure him that should increase your popularity, you should switch to hard difficulty otherwise there is a risk that he is killed instead (you'd probably want to make a backup to be on the safe side).
Or, you could capture and cure a zombie villager and breed more villagers.
All that is assuming that none of the rules are changing with 1.16, I've been waiting for the main release so I don't know much about what's changing.