Canker sore on inner labia lip

Noticed it was sore on friday, chalked it up to possibly sitting uncomfortably. yesterday it was raised and looked like a canker sore; raised, red with a flat white top. Today it is the same appearance but larger white top. It is not a pimple, it’s not fluid filled. It literally resembles a canker sore to a T. I 1000% know it is not STI related. I had a yeast infection but cleared that weeks ago. I have been sick and broke a bone on thursday and heard that this can sometimes happen due to illness or trauma. Just looking to see if this has happened to anyone else. What it is, what causes it, and how to treat it. I will be calling my OBGYN tomorrow.