Had 2 injections with emergency dentist yesterday so he could do some work on infected top back tooth. However he couldn't go ahead with it as the tooth wouldn't numb, I'm assuming because of the infection? I've had antibiotics and I think the tooth is improving but it's hard to tell as the injection site is so sore, is that common after dental work? Am due back with dentist tomorrow to have another go, am really worried now about having the injection. Anyone else experienced this?