Have you eaten anything crisp or sharp recently - it could just be a little tear on the roof of your mouth which I get sometimes or on my gum. Hopefully that will heal up but if not then ask the dentist if you need to have it looked at.
Do you remember Sunday drives?
Rupert Lowe and the “rowers” haha
but please be careful with the toothbrush. Agree with anno. Get dentist to check.
Anyway, don't happen to have a dental mirror.