It's hard to see but it does look a little swollen. I wouldn't freak out immediately, but it's definitely something I would keep a close eye on and get him to the vet if it gets worse or doesn't get better soon. I wouldn't mess with him for a couple days because of eating, but it might be worth it in 48 hrs to try and get a peek in his mouth gently to see if there are any obvious signs of a problem. Could be from breaking a tooth on a prior occasion which can heal on its own most of the time. Have his sheds been really good and complete in one piece? Sometimes a small piece can get stuck in the eye and cause a duct to clog and cause something like this.