Lowering pitch: yes, but rolling off throttle would have depressed the RRPM still further.
Allow me to elaborate. As she overpitched, pitch must be lowered , agreed. However, due to the correlated link to the throttle (this is type-specific for Robbies), lowering collective is not enough to stop the torque/spin. The solution is to simultaneously roll off momentarily when the collective is lowered - note that with the horn starting to sound (there's a very wide margin above the full stall, no dramas), the governor is not helping you maintain rrpm and rrpm has to be increased via autorotative descent. Once you stop spinning, forward cyclic to gain airspeed. A full auto is not necessary as once you picked up rrpm, you roll back on and the governor engages again. Then raise collective to add power as you fly away.