My dog is a 7 year old beagle cross that loves to wander in our lush paddocks. Yesterday morning he came back from his morning border patrol rather sheepishly and i noticed a red swollen patch on one side of his muzzle. It was obviously sore the way he didnt want me to touch it and he quivered his lip. I decided to monitor it closely to see if it warranted emergency vet care and it seemed to remain the same throughout the day. It didnt swell up anymore and he seemed to be ok with it. So I decided to not rush him to the vet. However at dinner time I noticed him trying to lick his lip repetitively and then i was shocked to see a weird round bump had appeared. It was clearly uncomfortable for him but there was no vet open at this time of night so I decided to watch him over night as he sleeps in bed with me. He is eating and drinking fine. He has been licking it most of the night but the lump seems to be the same size. It is now 4 am and I am wondering if I should take him to the vet today? What do you think could have caused this? I thought perhaps he just got bitten by an ant or stung by a bee or something.