I do think if you had a herpes symptom, you would know it, yes.
And no, I really don’t think you should ask your partner if he penis touched your genitals because even if they did, there clearly wasn’t enough contact to give you herpes.
Going to the ER with some stinging is the kind of thing that keeps your OCD going. Is your therapist working on cognitive behavior therapy with you? Have you considered medication for this?