I would say no you are not at risk for HIV in this instance. Here is why... I would bet since the wound was 3 days old and on your hand fingers area it was dry. When shopping you most likely bumped it in a way you did not even notice since are hand/fingers move touch etc. alot and most times we do not notice light bumps on them. The wound beginning to heal was probably dryer than usual do to light scabbing and healing and just cracked open and began to bleed a bit. Keep it washed and clean. Leave it unwrapped so it can get air to heal faster and be careful not to bump it to much in the future.
You absolutely cannot get HIV that way. HIV needs to be inside a host to be able to "live" and replicate and be infectious. It absolutely cannot survive outside the body on anything whatsoever. Not on grocery carts, not on food items, not on the bathroom stall...no where! If it did, just think about it, we would all be infected and we are not. That should be proof enough for you.