Severe pain in tooth after filling?

I received a filling for a relatively minor cavity one week ago, and ever since the novocain wore off, there has been excruciating, intermittent pain from that tooth. It is so horrible that it has frequently woken me up at night, and so severe that it makes me sweat and hyperventilate. The pain radiates from that tooth out towards the rest of my jaw, and even causes headaches sometimes.

This tooth did not hurt at all prior to the filling.

I recall that this dentist (he was NOT my regular dentist) seemed to rush the entire cavity-filling procedure -- he did not even seem to check my recently-taken X-Rays prior to initiating the filling. I had called in to the office one week prior to schedule this appointment and specifically mentioned I wanted to get a filling; yet when I arrived and sat on the dental chair, the dentist was all like "What are we here for?" And when I reminded him about the cavity I wanted fixed, he didn't even consult my X-Rays as a guide before proceeding. He just remarked "Oh, is it that small brown spot?" before winging it.

The entire filling procedure lasted about 15 minutes (which appears to have been rushed as even the smallest cavities take about 30 minutes from my regular dentist).

I'm afraid that this dentist carelessly drilled too deep into my tooth than it was necessary, or that -- since the entire procedure was rushed -- the filling is inadequately bonded.

(The pain is NOT caused by the filling being "too high", as that tooth is in the front and doesn't contact any other teeth when biting down.)

If I end up needing a root canal from this ordeal, and if this turns out to be the dentist's fault, what recourse do I have? Can I make a small claims case with a medical malpractice lawyer to get this dentist to contribute to the monetary costs required for my root canal?