My bf and me had unprotected sex .after few days he had sore(ulser) around his genital area. When he got tested for hsv 1 and hsv 2 ( blood test) the result was non reactive. Can blood test give accurate results.Can there be any other reason for those ulsers. And regarding STDs my question is STDs occur in person only if he had unprotected sex with a person who is infected.or is there a chance where neither had std before and they can become victims of std after having unprotected sex....please help me