Injection site marking method

A method of marking a site on a person's skin that has been injected with serum taken from a serum vial with a syringe having a needle and a syringe reservoir nose so that a user does not mistakenly inject a serum more than once, said method comprising the steps of:

• providing a marking apparatus including:
• a base member defining an interior area configured to be removably coupled to the serum vial adjacent a serum vial seal;
• a liquid retention member positioned in said base member interior area that is saturated with a colorized viscous liquid;
• coupling the base member to the vial adjacent the vial seal;
• inserting the syringe needle through said liquid retention member and through the serum vial seal such that serum is selectively drawn into the syringe reservoir and that the syringe reservoir nose contacts said viscous liquid of said liquid retention member;
• and
• injecting the syringe needle into the user's skin until the syringe reservoir nose contacts the user's skin so as to mark the user's skin with said viscous liquid.