The vet visited Dakota yesterday to take a look at his mouth. After light sedation, Dakota was utterly stoned. The vet agreed that there was some swelling on the left side of his mouth, but felt that it was mostly resolved. She suspects he was either stung by an insect or got a sticker or small stick stuck on the left side of his mouth several days ago, and it manifested most severely on Sunday. He's well on the road to recovery and will be ready to go back to work Saturday. The vet liked the eggbutt snaffle I'm using and thinks it fits him well. Great news on all fronts.