Nice relay. But no risk, be assured.
You can just say rectum and we get the point. If you have to alter a word, find another to use. Just saying. Anyway, no, this is not a risk for HIV. The only ways that people get HIV is from having unprotected vaginal or anal intercourse (penetrating) or sharing IV drugs. Touching and fingering will not result in HIV and hasn't for as long as the disease has been observed and studied. Air inactivates the virus. So, you are good . . . no worry of HIV from this.
Her finger in your a s s hole .sory