Inside of her mouth always feels sensitive like it's trying to heal after a burn.; Tongue with blisters - specially to the back of her mouth; Tongue is swollen - specially to the back of her mouth; Having blisters inside of mouth / specially to the back of her mouth / huge blisters inside of the mouth; when she is brushing her teeth, her mouth burns / she was eating gummy bears and her right side (where she chews), started to feel weird / the inside of her mouth always feels really hot / when she is flossing, she feels blood gushing inside of her m; This spontaneous case was reported by a consumer and describes the occurrence of ORAL MUCOSAL BLISTERING (Having blisters inside of mouth / specially to the back of her mouth / huge blisters inside of the mouth), ORAL DISCOMFORT (when she is brushing her teeth, her mouth burns / she was eating gummy bears and her right side (where she chews), started to feel weird / the inside of her mouth always feels really hot / when she is flossing, she feels blood gushing inside of her m), ORAL PAIN (Inside of her mouth always feels sensitive like it's trying to heal after a burn.), TONGUE BLISTERING (Tongue with blisters - specially to the back of her mouth) and SWOLLEN TONGUE (Tongue is swollen - specially to the back of her mouth) in a 48-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 037B21A; and 021B21A) for COVID-19 vaccination.     No medical history was reported.  Concomitant products included CELECOXIB (CELEXA [CELECOXIB]) for an unknown indication.   On 03-May-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 01-Jun-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 01-Jun-2021, the patient experienced ORAL MUCOSAL BLISTERING (Having blisters inside of mouth / specially to the back of her mouth / huge blisters inside of the mouth), ORAL DISCOMFORT (when she is brushing her teeth, her mouth burns / she was eating gummy bears and her right side (where she chews), started to feel weird / the inside of her mouth always feels really hot / when she is flossing, she feels blood gushing inside of her m), TONGUE BLISTERING (Tongue with blisters - specially to the back of her mouth) and SWOLLEN TONGUE (Tongue is swollen - specially to the back of her mouth). On an unknown date, the patient experienced ORAL PAIN (Inside of her mouth always feels sensitive like it's trying to heal after a burn.). At the time of the report, ORAL MUCOSAL BLISTERING (Having blisters inside of mouth / specially to the back of her mouth / huge blisters inside of the mouth), ORAL DISCOMFORT (when she is brushing her teeth, her mouth burns / she was eating gummy bears and her right side (where she chews), started to feel weird / the inside of her mouth always feels really hot / when she is flossing, she feels blood gushing inside of her m), ORAL PAIN (Inside of her mouth always feels sensitive like it's trying to heal after a burn.), TONGUE BLISTERING (Tongue with blisters - specially to the back of her mouth) and SWOLLEN TONGUE (Tongue is swollen - specially to the back of her mouth) outcome was unknown.            No patient history details were provided. Treatment details was not reported by the reporter. Reporter states that her friend recommended "some natural thing" for the immune system, but it's not working.   This case was linked to MOD-2021-269529 (Patient Link).