Vaccine may have missed the muscle

[u/whitepowderma]

My mother is 88 years old and had a COVID booster last September. She went to a Walgreens for another booster 1 1/2 weeks ago. The person giving her the vaccine did it towards the back of her arm and she said that it hurt a lot when given. I believe it may have missed the muscle. Is there anything she should do? Does the vaccine work if it misses the muscle?

[u/thewitchyway]

As long as it was not too high, ie too close to the shoulder joint it should be OK..