  We compute the phase diagram of the quark-meson model at finite temperature,
finite baryon chemical potential $\mu_B=3\mu$ and constant external magnetic
field $B$, using the functional renormalization group. Our results show that
the critical temperature increases as a function of $B$ at $\mu=0$, but for
values $\mu$ larger than about 210-225 MeV, the opposite behavior is realized.
As the magnetic field increases, the critical point $(T^*,\mu^*)$ moves from
large $\mu$, small $T$ towards small $\mu$, larger $T$ in the $\mu$--$T$ phase
diagram.
