The Human Chorionic Gonadotropin (HCG) should be stored in a sterile vial, you are injecting it into your body, don't want any pathogens introduced do you?
Also I wouldnt mix injecting oil based and water based solutions (I've read it can more easily cause abcess formation but don't quote me on this), Human Chorionic Gonadotropin (HCG) can be injected sub-q with a high gauge needle anyways. You could do it if you want, upto you to take a risk, it's nothing like immediately lethal, but personally I would do seperate injections.