  Recent observation of a mass enhancement in high magnetic fields in nearly
optimally doped cuprates poses several puzzles. For the suggested nodal
electron pocket induced by bidirectional charge order in high field, we propose
that the mass enhancement is very anisotropic around the small Fermi surface.
The corners of the pocket are proposed to have a big enhancement without any
enhancement along the diagonal nodal direction. A natural mechanism for such
angle dependent mass enhancement comes from the destruction of the Landau
quasiparticle at hot spots on the large Fermi surface at a proximate quantum
critical point. The possibility of a divergent cyclotron effective mass is
discussed within a scaling theory for such a quantum critical point. We
consider both a conventional quantum critical point associated with the onset
of charge order in a metal and an unconventional one where an antinodal
pseudogap opens simultaneously with the onset of charge order. The latter may
describe the physics of the strange metal regime at zero magnetic field.
