hi i shook hands with someone of unknown hiv status and my fingernail cut into his skin. I dont believe i was bleeding at the time but i noticed that he was bleeding from the contact as he said ow! i dont know how deep it was though. i did have a day or so old cut that didnt look completely scabbed over. the man i shook hands with is gay and i dont know his status again. do i have anything to worry about should i get post exposure shots? please help.