This is not a risk for HIV transmission. The only risks are to have unprotected vaginal or anal sex or share IV needles to INJECT drugs. Air inactivates the virus. A needle stick is just that and not an injection. There is no risk from being stuck with the sharp end of a lancet. There is exposure of air. There is no risk to your child. However, make sure your child is in a safe place overall. Don't know what the person was injecting but if there is drug use near your child, remove your child from that situation.
The only risks for HIV are:
1) Having unprotected anal or vaginal sex, or
2) sharing intravenous needles with IV drug users.
The only exception is an HIV+ mother breastfeeding a newborn infant.
If you do not engage in any of the activities I mentioned above with someone HIV+ or whose HIV status is unknown to you, you will NEVER have to worry about getting HIV. There is no "what if" question that you could imagine about this event that would make it a risk for HIV.