  We have collected a new deep {\it Chandra X-ray Observatory} ({\it CXO})
exposure of PSR B2224+65 and the `Guitar Nebula', mapping the complex X-ray
structure. This is accompanied by a new {\it HST} H$\alpha$ image of the head
of the Guitar. Comparing the {\it HST} and {\it CXO} structures in 4 epochs
over 25 years, we constrain the evolution of the TeV particles that light up
the filament. Cross-field diffusion appears to be enhanced, likely by the
injected particles, behind the filament's sharp leading edge, explaining the
filament width and its evolving surface brightness profile.
