Regarding facial / forehead sweating: Hidrex offers the face mask, to treat facial and/or forehead sweating. The mask with electrodes costs 90€ and has to be used together with the Hidrex machine Hidrex PSP1000, which costs 669€.
Regarding scalp / neck (and also chest or back) sweating: Hidrex offers also special applicator pads to treat excessive back, chest, scalp and/or neck sweating. Here is a picture of the small one and here a picture of the bigger one. The small and the big applicator cost each 60€ without electrodes and 90€ with electrodes. To use these two applicators you will also need the Hidrex PSP1000 machine.