Oral interaction with a cocaine shooter and its STD possibilities

Patient: I just performed oral sex (a blow job) on a male I was interested in seeing, then found out afterward he shoots cocaine. He says he never shares needles, but I realize the behaviors of addicts and that there is always a risk he may have something from shooting, and that I could contract it from giving him oral. My question is how long do I have to wait to have tests performed to show results either way, and statistically what are the chances based on what sexual action I performed on him?