The rash sounds like chafing or irrtiation, certainly nothing like warts, herpes, or anything else unlucky. Lubrication before and 1% hydrocortisone after should suffice.
It's hard to say what your risk of cintacting the warts is or was. If you have nothing visible (and you'd dee 'em if you had them), then you should be OK. Has your girlfriend had them treated? If not, she should and should get regular Pap smears.
Best.
Dr. Rockoff
Dr. Rockoff