The card speaks neither of applying it “neat” nor of diluting it. It says: apply externally to the required areas as needed; the composition (INCI) is distilled glycerol and purified water, and the method of use should follow the information on the packaging. It must not be used on open wounds, and contact with the eyes and mucous membranes should be avoided.
General information (not a manufacturer's instruction): in case of irritation or an allergic reaction, stop using it and see a doctor.