###Human: Why do I have dry mouth two months after unprotected oral sex? ###Assistant: Hi. A fourth generation HIV duo test is considered reliable and conclusive if it is still negative after six weeks. Most STD (sexually transmitted diseases) specialists consider this six weeks gap as the upper limit of the window period for an HIV duo test result to be considered final. Since your exposure was two months back and your last HIV duo test was almost eight weeks after exposure, your test result is reliable and conclusive. You do not need to worry about HIV from that particular episode. For more information consult a HIV AIDS specialist online -->