Gum abbess or ulcer?

[Sophie2525]

Sorry poor photo but can anyone advise? It’s painful but not unbearable. Suppose to be going out today but worried if it’s a possible infection

It's really hard to tell from the photo!
Is the tooth next to it sore too?

Rinse often with hot salty water, and if it hasn't gone in 3 days or so get it checked out by a dentist