Your symptoms, especially the itching and watery discharge, suggest a fungal infection (like athlete's foot) rather than a bacterial one. Neosporin is an antibiotic and will not cure a fungal infection. You should stop using it. You likely need an antifungal treatment, such as clotrimazole or terbinafine cream. However, because you are also experiencing pain and stiffness, there is a risk of a complicating bacterial infection like cellulitis. You should see a healthcare professional immediately for a physical exam to get the correct prescription (which may include oral antibiotics or antifungals). Keep the foot clean and dry in the meantime.