Does your boyfriend have HIV? Regardless, this is not a risk. Blood exposed to air outside the body is not infectious. Also, that is not a route of transmission. In an adult, only unprotected unprotected anal or vaginal sex and sharing IV drug needles with infected users is a risk for possible HIV infection.
Chima7 asks an important question you neglected to answer. Does your boyfriend, a known person to you, have HIV? Because I'm guessing he doesn't. Which would make this even more of unnecessary worry. But EVEN if he did, this isn't how you get HIV. Chima tells you the ways and those are the only ways. So, even if you touched blood and had a small wound, you will not get infected. This is zero risk.