Hi I Performed Unprotected Oral Sex On Another Guy On

Hi i performed unprotected oral sex on another guy on septermber 13th i had a few cuts not to mention i cut my lip while performing he ejaculated in my mouth and i spit it out...i was told to get tested by one of my ex's because he had syphilis turns out i had it too and i did a full checkup on october 7th i did a rapid blood hiv test my hiv results were negative how accurate would these results be being that is was only two weeks post possible exposure?