HIV is unable to reproduce outside its living host (unlike many bacteria or fungi, which may do so under suitable conditions), except under laboratory conditions; therefore, it does not spread or maintain infectiousness outside its host.
HIV is transmitted by;
Unprotected penetrative anal and/or vaginal sex
Sharing works with other IV drug abusers
Mother to child
You can't contract Hiv from being scratched.It's never happened in 30 years of the Hiv pandemic.You can stop worrying now.