Welcome to the forum.
I assume (and certainly hope) you discussed this exposure event with the hospital or clinic infection control team, and that an ID specialist or other HIV/AIDS expert prescribed your PEP regimen and is following you. If so, that person's advice is just as valid as ours on this forum, perhaps more so. Dr. Hook and I have little direct experience in prescribing PEP and in following people after known HIV exposures.
That said, you had a low risk exposure. Conjunctival exposure to HIV infected secretions is one of those listed risk factors, based on common sense and general knowledge of HIV transmission mechanisms, with few known cases of transmission. I am unaware of any case reports of documented transmission by this route. Also, what is the infectiousness status of the source patient? "Stage 2" isn't helpful; the important information is his or her viral load and whether s/he is on antiretroviral therapy. If the viral load is low, and especially if it is undetectable on ART, then there probably was no transmission risk at all.
Your immediate questions about test reliability and timing get to the issue of whether, when PEP doesn't work, seroconversion time or time to detection of HIV DNA, are delayed and by how much. To my knowledge, there are no data, only common sense assumptions by knowledgeable experts. However, most experts believe seroconversion still would occur within a month of stopping PEP; and that PCR would be positive within 7-10 days of completing PEP. I am unaware of any reports otherwise, i.e. of it taking a month after completing PEP for PCR to become positive. Therefore, it is likely your current test results are 100% reliable.
I'll be interested in further information about the patient's viral load and ART. But even if not on treatment and high VL, I would judge the chance you have HIV -- in view of the nature of the exposure, plus PEP, plus your current test results -- as zero or close to it. However, as implied above, you should have asked these questions of your own provider. If you have not, you definitely should do so; and follow his or her opinions and advice if they differ from mine.
Best wishes for your continuing medical training and a successful career.
Thank you for your input,
The patient's viral load was 40K and he was on Kaletra at the time. Before starting Kaletra about 8 months prior, his viral load was about 120K.