I am not familiar with the terminology - fisherman's feet problem. Probably your daughter has one of the keratodermas. The skin is thick and it cracks. When the crack is deep it creates a raw area which then becomes painful. Therefore it is important to make the patient comfortable by keeping the skin soft and supple, prevent cracks and hence minimise pain. Long term outcome depends upon the diagnosis and possible cause.
Fill in the deep painful cracks with any antibiotic ointment. Then rub the keratolytic ointment on the thick skin, e.g. salytar ws ointment. If this does not work then ointments have to be formulated based upon clinical findings.