Damn bro, my doc calls me the next day with my results.
Just tell him the truth, that you took an extra shot. See if he wants to put the test off for a little while. I tell my doc everything, when I took my last shot of test, winny, whatever it may be. When it comes to your health and lab results, just be honest. What's the worst that going to happen? He might bitch and moan, but just deal with it and see what he wants to do.