is it supposed to hurt/cause discomfort after dental injections are given?

i went to the dentist earlier this week due to a lower molar on the right side that had been giving me trouble for some time, it just kept getting progressively worse. while there, i found out that i had several large cracks in the tooth, ut he didn't mention anything about any infection being in the root. however, because the tooth is causing me pain, fever, and i cannot put pressure on it, the dentist decided the best course of action would be a root canal, which has been scheduled for later this week.i've already been through this process for the other side, so i am not looking forward to it. my only concern is the cracks that are already in the tooth. will the drilling compound this problem? as my visit was ending, he could tell that i was uncomfortable and so he offered to give me an injection to numb the area for awhile. i know that i was injected twice, and the last was a long acting numbing one. when he was just aout finished, i felt a very sharp jolt, which he told me was my nerve. i was numb for the remainder of the day and night, but the next day, my jaw hurt, half of my lower lip was swollen, my ear hurts, as does part of my cheek. i didn't do anything for a couple of days, except take the anibiotic as instructed. i thought this might help, and i also thought i needed time to let the shot wear off completely. unfortunately, the dentist is not in the office on fridays, ut they do have an outgoing message that if a patient is experiencing a problem they should go to the er. would this qualify? what else could be causing this? is it something i'm doing? also, after this side is taken care of i'm supposed to go back to my oral surgeon to make sure a bone graft that was placed in my extraction site has caused my bone to harden enough for an implant. what will this entail? will it hurt? how is it treated? thank you.
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If he hit the nerve, that would be why your lip swelled up and your ear hurts. Your dental nerves are connected to virtually everything in your face. I don't know if going to the ER will help, honestly.
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