I went back to the doctor yesterday and he thinks I have a Hematoma; My arm got this stinging and it just stung; It was hardened and it just started swelling/Top of my arm is real hard; Took my booster shot, Moderna; hurt me really bad/My arm got this stinging and it just stung; My arm began to swell up around the injection site; it had an awful looking place around it and it stayed that way; I have had a severe reaction to the shot; The 'spot' was real blue and green and don't know, it didn't look good/blue is completely down to my elbow; This spontaneous case was reported by a consumer and describes the occurrence of VACCINATION SITE DISCOLOURATION (The 'spot' was real blue and green and don't know, it didn't look good/blue is completely down to my elbow), HAEMATOMA (I went back to the doctor yesterday and he thinks I have a Hematoma), IMMUNISATION REACTION (I have had a severe reaction to the shot), VACCINATION SITE PAIN (Took my booster shot, Moderna; hurt me really bad/My arm got this stinging and it just stung) and VACCINATION SITE SWELLING (My arm began to swell up around the injection site; it had an awful looking place around it and it stayed that way) in a  patient of an unknown age and gender who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.    On 22-Apr-2022, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In April 2022, the patient experienced VACCINATION SITE DISCOLOURATION (The 'spot' was real blue and green and don't know, it didn't look good/blue is completely down to my elbow), IMMUNISATION REACTION (I have had a severe reaction to the shot) and VACCINATION SITE SWELLING (My arm began to swell up around the injection site; it had an awful looking place around it and it stayed that way). On 22-Apr-2022, the patient experienced VACCINATION SITE PAIN (Took my booster shot, Moderna; hurt me really bad/My arm got this stinging and it just stung). In May 2022, the patient experienced HAEMATOMA (I went back to the doctor yesterday and he thinks I have a Hematoma) and VACCINATION SITE INDURATION (My arm got this stinging and it just stung; It was hardened and it just started swelling/Top of my arm is real hard). At the time of the report, VACCINATION SITE DISCOLOURATION (The 'spot' was real blue and green and don't know, it didn't look good/blue is completely down to my elbow), HAEMATOMA (I went back to the doctor yesterday and he thinks I have a Hematoma), IMMUNISATION REACTION (I have had a severe reaction to the shot), VACCINATION SITE PAIN (Took my booster shot, Moderna; hurt me really bad/My arm got this stinging and it just stung), VACCINATION SITE SWELLING (My arm began to swell up around the injection site; it had an awful looking place around it and it stayed that way) and VACCINATION SITE INDURATION (My arm got this stinging and it just stung; It was hardened and it just started swelling/Top of my arm is real hard) outcome was unknown.            No concomitant medications information was not reported.  On 28-Apr-2022, patient went to see family doctor, but the spot was real blue and green and don't know, it didn't look good and thought it would go away.  They kept compression on it and then on an unknown date (referred as last Friday), patient arm got this stinging and it just stung. It was hardened and it just started swelling and top of arm was real hard and the blue was completely down to elbow. Patient meant it was blue. So, patient went back to the doctor yesterday and thought patient had a Hematoma in there, but said x-raying it or doing a sonogram on it not going to help it. So, thought patient had a severe reaction to the shot.  No treatment medications were provided.   Reporter did not allow further contact