It might be because there’s some food debris under your gums. The food debris will irritate the area and cause inflammation. Therefore, removing the food debris by brushing or flossing can make your gum look normal again.
However, the inflammation might still persist for days. This could be an early form of gum disease where the build-up of bacteria around your gumline is continuously irritating the gums (and thereby causing inflammation). You should go to the dentist as soon as possible before the gum disease gets worse (and might cause tooth loss or make you undergo an expensive surgery).
Other causes of swollen gums
Aside from food debris and gum disease, other potential causes of swollen gums are:
- Infection (viral or fungal)
- Malnutrition (e.g. lack of vitamin B complex and C)
- Side effect of medications (might be caused by blood pressure medications and others)
- Sensitivity to toothpaste or mouthwash (might be too harsh)
- Poorly fitting dentures