Your possibility is 1/1000 but it is still there, an hiv test 3months post exposure is conclusive, so take the test now and you will have your answer you should be fine...
All HIV questions should be posted in the HIV community, so please any follow up HIV questions please post them there.. As for STD's, you did have a risk so here are testing times:
Gonorrhea and Chlymida-1 week post exposure
Syphilis-6 weeks
Herpes-4 months
and as said above HIV is 3 months
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