This asymmetry suggests localized skin thickening, which is commonly caused by friction (a callus) or a fungal infection like moccasin-type athlete's foot. To soften the tough, white skin, you can use a cream containing a keratolytic agent like urea (20 to 40 percent) or salicylic acid. If a fungal infection is possible, an over-the-counter antifungal cream such as clotrimazole or terbinafine may help. Apply these after gently washing and thoroughly drying your foot. Please avoid cutting the thick skin yourself. I recommend seeing a podiatrist or primary care doctor for a proper evaluation to ensure you use the most effective treatment.