Retreating blade stall is the primary limiting factor of a helicopter's never exceed speed, VNE.
Most helicopter designs compensate for this by incorporating a certain degree of vertical "flap" movement of the rotor blades.
In all cases, the pilot may compensate the induced roll with left or right cyclic control input (as determined by the rotation of the rotor) up to a degree.
However, the rapid rate of change of blade flex and angle of attack causes uncontrolled longitudinal twist and severe vibration in later stages, resulting in total loss of cyclic control if left unchecked.
Assuming no rotor damage, recovery from this condition is possible and described below (see § Flight performance during a retreating blade stall).
As the aircraft approaches retreating blade stall conditions, it will shudder and the nose will begin to pitch up.
If forced to continue the acceleration via flight controls (forward cyclic + collective), it may roll to the side of the retreating blade.