help!!!!!

okay so I have this place downstairs and I’m not sure what it is. I just shaved the other day and I just some sea salt in my bath and I’m thinking maybe that was the cause ?? but anyway I will leave a pic below. it doesn’t hurt or anything and it doesn’t burn when I pee. it’s just there ? was it a allergic reaction. Maybe too much salt ?

I have been tested for herpes before so I am almost certain it isn’t that and I have googled symptoms and I have none.