Why Does Flyback Current Destroy Darlington Buffered Op-Amp?
Put a resistor in series with the opamp negative input.  That will limit the current into the opamp when voltage spikes happen.  10 k&Omega; should work.

Check the stability.  Perhaps the opamp is oscillating.  With the resistor in there from #1 above, you can add a small cap directly between the output and negative input to add stability.  That will also slow the response, so you have to juggle the tradeoff.  A few 10s of pF up to maybe 100 pF should be all you need unless this is a very unusual opamp.

I'd add a Schottky diode in reverse from the output to ground.  That will clip any negative spikes.