The motion of a tracer particle embedded in a complex soft material is a paradigmatic topic in statistical physics and physical chemistry. On the one hand, the motion of the fluctuating tracer can be considered a stochastic process in a heat bath provided by the surroundings. Classic models of statistical physics, like the Brownian random walk, have been investigated in this setting. On the other hand, the tracer can be used as a probe for studying the environment. For both cases, often colloids are used as probe particles in complex fluids. Commonly, no information on the bath structure is obtained. We go one step further by driving the colloidal probe strongly while simultaneously investigating the surrounding medium by particle resolved optical microscopy. We use confocal fluorescence microscopy with coupled optical tweezers and tailor-made core/shell polymer colloids as sample particles. The positions of thousands of colloids are tracked in 3D while a special probe particle trapped by the optical tweezers is moved through the sample. We observe the spatial extent and anisotropy of the structural relaxation in the prototypical model system of a dense dispersion of spherical colloids. Testing states close to the colloidal glass transition, we measure the local viscoelastic flow around the probe, local fluidization of the amorphous solid, and the spatial extent of cooperative structural relaxation. We find a local meting of glass with a finite extent and clear fore-aft asymmetry.