Hello. As your risk was oral sex, this is not a way that HIV is transmitted. Adults get HIV from unprotected vaginal or anal sex or sharing of IV drug needles. You did not risk HIV. In testing for peace of mind, 28 days is the time frame to receive a conclusive result with a 4th generation test. As you didn't need to test in the first place, your 25 day result of negative makes sense as it was a non risk exposure. However, in general, waiting until 28 days is important for a conclusive result. We wish you the best and are closing this thread.
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There is a reason you were supposed to wait until at least 28 days for the 4 gen so adding another test doesn't allow you to get a useful answer. This isn't a high school biology exam where you cheat and maybe pass.
You were advised before about your oral incident so it seems you let your fears get in the way of reason.