If a root canal was done, sometimes there's some post-operative discomfort with the treatment. I would advise you go back to your dentist to check to see if theres any problems because the pain should improve rather than worsen. The antibiotics may be necessary but it depends on the extent of the infection. The antibiotics would help with maintaining the spread of infection but it is definitely not the cure for it. The root canal should have cleaned your canals of your tooth out to help your body remove whatever infection is left and that should help with the pain, as well as removing the infected
nerveNerve biopsy
Nerve conduction velocity in the tooth.