caller notes "a lot of bleeding."; booster; went into the "vein vs the muscle/ believed it was administered subcutaneous instead of intramuscular; bruising; Her arm and shoulder hurts; Her arm and shoulder hurts; hematoma; warm to touch; hard lump underneath; This is a spontaneous report from a contactable Nurse (patient). This 62-year-old female patient received 3rd dose of BNT162B2 (COMIRNATY, lot number FE3690, expiration date 30Nov2021) at single dose subcutaneous in right arm on 29Oct2021 maybe around 11:00 at 62-year-old for COVID-19 immunization. Her shot was supposed to be at 10:45 but because she was getting it in her right arm it was delayed, so it was probably around 11:15. She clarified it was filled at 10:46, so she doesn't know what time it was given, maybe around 11:00.  Medical history included high blood pressure, anti-cancer, GERD (Gastrooesophageal reflux disease), double mastectomy and was post chemo, hemochromatosis, breast cancer. Patient stated that none of the medical conditions should be related to the vaccine. Concomitant drugs included omeprazole for GERD, tamoxifen for anti-cancer, and losartan for high blood pressure.  She confirmed she had not begun any new medications within the 2 weeks leading up to her events. She was not on any blood thinners or aspirin. The medications she has been on she has been on for a while. Historical vaccine included first dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Lot: EL9269 Expiry date: 30May2021) intramuscular at right deltoid on 20Feb2021 at 62-year-old; second dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Lot: EN6198 Expiry date: 30Jun2021) intramuscular at right deltoid on 11Mar2021 at 62-year-old and felt like she was hit by a truck, experienced hematoma, warm to touch, lump underneath, muscle aches, pains, extreme fatigue and difficulty walking. It was also reported that she had her first 2 shots and had no problems; she did have side effects the following day with her first two shots.  For the first shot, she had no side effects, no arm soreness. For the second shot, she had no arm soreness. She got the second shot around 11am on a Friday and woke up at 2:00am and felt like she was hit by a truck. She had muscle aches and pains, extreme fatigue, difficulty walking. Then about 14 hours later, everything was gone. Patient received her booster dose "today" (on 29Oct2021). She stated by the time she got to her car, she had soaked through the cotton ball that the administrator of the vaccine had applied after the injection. Patient noted a lot of bleeding. She believed that the one who gave her vaccine may have hit a "blood vessel" and it went into the "vein vs the muscle. Patient did not feel as though it was administered IM or any clotting effects. Patient noted her arm was warm to the touch with a hematoma underneath. She would also like to know what Pfizer recommends, whether it be a warm compress or cold compress for hematomas at the injection site. Patient stated that they "pinched up my arm" and she felt as though if the skin were pulled taunt it would have been better based upon her anatomy/body. She had grabbed paper towels because there was a lot of bleeding. This happened around 11:00AM and now (as of 29Oct2021) there was bruising. The person administering the vaccine didn't aspirate. She believed the person pinched up on her skin, she wasn't paying attention. She believed the person administering hit a blood vessel for it to cause that much bleeding. After the third dose, she has bleeding and bruising. She sent a pic of her arm to her friends and they responded asking what it was. Her arm and shoulder hurts, it's already bruised. She clarified there was a hematoma, the area was warm to touch, and there was a hard lump underneath. It's not a typical reaction to an injection. She was sure it was due to technique. She believed it was administered subcutaneous instead of intramuscular. No Investigation Assessment performed.  Outcome of the events was unknown.  She considered it serious. She stated the event being medically significant had yet to be determined. She did not need a trip to the ER, she was just watching for any signs. There was warmth and a hematoma there, so she did not know. Reaction assessed per Primary Source Reporter according to Method of assessment: Global Introspection was related for event "third dose: believes the vaccine was given in the vein instead of muscle".; Sender's Comments: Based on a temporal association, a possible contributory role of suspect drug BNT162B2 to the events vaccination site haemorrhage, contusion, pain in extremity, arthralgia, haematoma, feeling hot, skin mass cannot be completely excluded. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators, as appropriate.