The internal structure of a slowly rotating, steadily accreting, charged black hole that is undergoing mass inflation at its inner horizon is derived. The approach is to introduce a small rotational (axial dipole) perturbation to a spherically symmetric black hole. The equations governing the angular (dipole) behaviour decouple from the radial (monopole) behaviour, so all conclusions regarding inflation in the spherical charged black hole carry through unchanged for the slowly rotating black hole. Quantities inflate only in the radial direction, not in the angular direction. Exact self-similar solutions are obtained. For sufficiently small accretion rates, the instantaneous angular motion of the accretion flow has negligible effect on the angular spacetime structure of the black hole, even if the instantaneous angular momentum of the accretion flow is large and arbitrarily oriented.