What is this?! Dd woke up and was eating breakfast came and showed me this saying it hurts a lot

Honestly, I have no idea. I get them too though. They're like blisters in the mouth. I get them when I'm stressed but I've never thought to ask what is way.

Canker sore?

Looks like the beginning of a canker sore

It's more of a bump though almost like a cyst. Aren't canker sores flat?

If it's anything like the "sores" I get it's got clear fluid in it. It'll pop then instantly get better. I'd suggest leaving it alone, if you can. I don't think it's harmful in the long run. I've got them for as long as I can remember.

Swishing warm salty water in her mouth will help with the pain. I used to get them alot.

It's a mucous cyst

Does it have clear liquid in it?

They pop and get better

Everyone gets them but in different places

Do salt water rinses it mar relieve any pain

Could be an abscess. I'd take him to his dentist to have it evaluated.

May have scratchEd his gum eating and got infected

I've gotten those before too. Have her swish salt water & you can put some orajel on it.