Have you first check to see if by chance you have food particle suck between your teeth cause the swelling? If you have then this is additional information I was able to find for you.
Here are some reason why you may have swollen gums. I would suggest that you might want to visit a dentist.
Gums – swollen Definition:
Swollen gums are abnormally enlarged, bulging, or protruding. Alternative Names: Swollen gums; Gingival swelling Considerations: Gum swelling is quite common and may involve one or many papillae (the triangular-shaped bits of gum between adjacent teeth). Occasionally, the gums swell significantly, obscuring the teeth altogether.
Infection by a virus or fungus Gingivitis Poorly fitting dentures Sensitivity to toothpaste or mouthwash Side effect of a drug such as Dilantin or phenobarbital Malnutrition Scurvy (Vitamin C deficiency) Pregnancy (1st or 2nd trimester)
I hope this information help