You had no risk. This is not how HIV is spread. HIV can only infect INSIDE the body, which is why an unprotected penis inside a vagina or anus is a risk as well as sharing drug needles with infected users. Nothing else you can make up in your head is a risk. Move on with your day.
this section is for HIV only, not all std/sti. you were at no risk from a fist bump. the only ways for HIV transmission in adults would be unprotected vaginal, or unprotected anal sex, and sharing needles/syringes for IV use. zero risk, now you can get some rest.