Having damp feet is a risk factor for developing fungus of the feet, either athlete's foot (fungal infection of the skin of the foot) or nail fungal infections. That being said, many people have damp feet without contracting nail fungus or athlete's foot.
The fungus that causes these two conditions tend to live in shared group areas, like gymnasiums or dormitory bathrooms. Therefore, it is important to take precautions in these areas (for example wearing shower shoes in the public shower stalls). Additionally, it can be helpful to change your socks frequently if you have a tendency to sweat a lot and have a history of fungal infections of the feet in the past. Similarly, keeping your shoes clean and dry is important.
If you do feel like you are contracting a fungal infection, go see your primary care doctor
to confirm the suspicion. Athlete's foot is actually fairly easy to clear up with good foot hygiene and a topical anti fungal cream. Nail fungal infections, however, are much more stubborn, and they usually require taking prescription oral anti fungal medications.
Please discuss further with your primary care doctor.