Make sure your bun is still eating and drinking semi normal amounts. You don't want this to also turn into dealing with GI stasis as well. If your bun has stopped eating or is having difficulty eating, you'll need to get your bun checked right away, as there may be damage to the jaw or incisors that's causing mouth pain and the lack of appetite. A rabbit shouldn't go more than 12-24 hours without eating an adequate amount of food, before it's considered an emergency situation.
If your bun is still eating and drinking pretty normally, and acting pretty normal, then it usually means there probably isn't a significant amount of pain, and it's likely not an emergency needing immediate vet care. Though if you do have any concerns or feel something is wrong, best to get your bun checked by a knowledgeable rabbit vet right away, especially if there's a split in the skin that might require stitches.
Veterinary emergencies
(Massachusetts Rabbit Vets)
https://wabbitwiki.com/wiki/Massachusetts