Why not work in SI units in which case the unit will be V/m² as suggested here Units before and after compute_current_source_density - #4 by larsoner ?
epochs_MNE = mne.EpochsArray(epochs_array[ :,:64, :], info_temp) # don't convert to µV
# CSD calculation (input is V so output is V/m²)
epochs_MNE_CSD = mne.preprocessing.compute_current_source_density(epochs_MNE)
epochs_MNE_CSD.get_data()
Mathieu