a bruise comes from leakage of blood from a capillary wall of a blood vessel....he may have nicked a blood vessel while he was injecting or the BA from the test may have aggitated a vessel or capillary and caused bleeding....put some ice on it...dont use heat it may cause more bleeding....

other items may have added to this condition(if you can call it that)....aspirin like with an ECA stack and asthma meds like clenbuterol are known blood thinners and could increase your chances of a bruise..........

tell him to skip that site until it has time to recover.....no big problem......viper