How likely it is for a bacterial vaginosis infection after menstruating to go away on its own? barely any symptoms, discharge and itchiness with tight

This is quite...: It is quite likely since BV is most commonly caused by pH changes that occur in the vaginal vault due to hormonal changes. For most, the overgrowth and "infection" resolves on its own as pH returns to normal.

Unknown: Some people share the exact kind of bacteria in their vagina as those who have BV yet don't show symptoms. It's not clear what factors lead to the development of these cases, but bleeding is one of them and it's possible that once the bleeding stops, the body begins to clear the BV. I would give it a week before treating.