I work as a massage therapist. Can I contract HIV from a client if I had small hang nail or unnoticed scratch? If client had the same, maybe a pimple.

Very unlikely. Contracting HIV that way would be very difficult. Even with unprotected sex between an infected & uninfected person, transmission rates are surprisingly low. In order to transmit from your client to you, his/her body fluids would need to mix with yours AND his/her viral load would need to be high enough to actually infect you, so he/she likely would be newly diagnosed or untreated. Good luck!