burns similar to poison ivy; Mix of blisters, irregular patches and raised round blotches; am I suddenly allergic to amoxicillin because of the vaccine; Cross interaction; A rash appeared along underwear line/irregular patches; hives and welts on pelvic area; Mix of blisters, irregular patches and raised round blotches; Itches; 12 hours after receiving booster; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) via COVAES. The reporter is the patient.  A 57 year-old female patient (not pregnant) received bnt162b2 (BNT162B2), administered in arm left, administration date 18Nov2021 13:30 (Lot number: FH8020) at the age of 57 years as dose 3 (booster), single for covid-19 immunisation; amoxicillin (AMOXICILLIN), since 10Nov2021 (Batch/Lot number: unknown) for dental operation. Relevant medical history included: "Known allergies: Sulfa medications" (unspecified if ongoing); "Asthma" (unspecified if ongoing); "Allergies" (unspecified if ongoing); "Bipolar depression" (unspecified if ongoing); "Hypothyroidism" (unspecified if ongoing); "Dental work" (unspecified if ongoing), notes: 10 crowns permanently seated. The patient's concomitant medications were not reported. Past drug history included: Biaxin, reaction(s): "Known allergies: Biaxin". Vaccination history included: Bnt162b2 (Dose Number: 2, Batch/Lot No: ER8737, Location of injection: Arm Left, Vaccine Administration Time: 13:30), administration date: 09Apr2021, when the patient was 57 years old, for COVID-19 immunization; Bnt162b2 (Dose Number: 1, Batch/Lot No: EP6955, Location of injection: Arm Left, Vaccine Administration Time: 13:45), administration date: 18Mar2021, when the patient was 57 years old, for COVID-19 immunization. The patient was not diagnosed with COVID-19 prior to vaccination, had not received any other vaccines in 4 weeks prior to the COVID vaccine and was not tested for COVID-19 since vaccination.  The following information was reported: IMMUNISATION (medically significant) with onset 18Nov2021 13:30, outcome "not recovered", described as "12 hours after receiving booster"; BURNING SENSATION (medically significant) with onset 19Nov2021 02:00, outcome "not recovered", described as "burns similar to poison ivy"; PRURITUS (medically significant) with onset 19Nov2021 02:00, outcome "not recovered", described as "Itches"; RASH (medically significant) with onset 19Nov2021 02:00, outcome "not recovered", described as "A rash appeared along underwear line/irregular patches"; URTICARIA (medically significant) with onset 19Nov2021 02:00, outcome "not recovered", described as "hives and welts on pelvic area"; BLISTER (medically significant), RASH MACULAR (medically significant) all with onset 19Nov2021 02:00, outcome "not recovered" and all described as "Mix of blisters, irregular patches and raised round blotches"; DRUG HYPERSENSITIVITY (medically significant) with onset 19Nov2021 02:00, outcome "not recovered", described as "am I suddenly allergic to amoxicillin because of the vaccine"; DRUG INTERACTION (medically significant) with onset 19Nov2021 02:00, outcome "not recovered", described as "Cross interaction". In the middle of the night, a little over 12 hours after receiving the booster, a rash appeared along underwear line, progressing into the morning with hives and welts on pelvic area; it worsened as the day progressed, on buttocks, legs, torso, axillary region, posterior neck, and head. Mix of blisters, irregular patches and raised round blotches. It itched and burned similar to poison ivy. The patient inquired if it was from the vaccine or was she suddenly allergic to amoxicillin because of the vaccine or was it a cross interaction. She started amoxicillin 9 days ago for dental work, 10 crowns permanently seated. She was waiting for a call from the doctor. The action taken for amoxicillin was dosage permanently withdrawn. Therapeutic measures were taken as a result of burning sensation, pruritus, rash, urticaria, blister, rash macular, drug hypersensitivity, drug interaction. The patient reported hydrocortisone and diphenhydramine hydrochloride (BENADRYL) barely touched it.