I went to a barber today. After haircut, he took out a blade which was already half from a packet in front of me. Then the cleaned the minor hairs at back of head. I didn't feel any cuts at back of head after that. Just some razor burn. After coming home (5 mins later) I applied after shave and it burned. I asked my mom and bother they confirmed no visible cut was there. I'm fairly sure blade was new but what are chances of hiv from such an exposure ( in percentage if possible) and should I do anything now ?