I have a white ulcer in the the inside of my bottoms lip I’m concerned it’s herpes simplex
Same person - had oral sex with someone that has slept with two other guys recently, she said she was clean,
It's most likely a canker sore caused by repeated rubbing of your lip against your teeth. Wait a few days and it should go away. You can try a salt water mouth rinse too. Mine usually go away in a day.