Hi myself and my 2 year old lightly got pricked by a safety pin, i didnt see any blood but the pin was black so could have dried blood on it could this cause hiv to be transmitted for either or both of, i live in south africa where hiv is common?

Unlikely: I find this unlikely from the description of the incident. HIV is a fragile virus that transfers best when fresh wet blood from an infected host is passed into a wound of a victim. Once it has dried out it is considered likely inactive. This differs from the Hepatitis B virus that might pass that way. To even consider HIV you must have that pin encounter an active HIV patient in close timeframe