Bubble on Khaki Campbell beak?

[Makennapatt26]

Hello everyone! My Khaki Campbell just developed this bubble under her beak tonight, and i have no clue how! I was trying to read up, but just couldn’t find anything really helpful. Here are some pictures! All help is welcome! Thank you

 

[Isaac 0]

It could be some bruising, so if that were the case no treatment would be needed, but if she were mine I'd like inside her mouth for anything abnormal just to be sure.