Feet skin infection. Keeps coming back.

My aunt lives in a remote village in UP. During rainy seasons she has to sometimes walk in water, mud and hard ground. As a result she has persistent burning sensation and painful infection between her toes. For the past one month or so, she developed a few callouses in her feet which later got cut and now are increasing in radius. The skin around them is hard and the sensation alternates between itching and painful. A local doctor had a look and said that the callous area would have to be cut and removed from the feet. Previous medication used are - panderm and vaseline but were not very effective. Please tell me what can be done in this situation to avoid the operation and get a permanent solution to the problem which keeps coming back.