Hole won’t heal

So I’ve had a literal hole on the bottom of my big toe for a couple months now. Only about an inch or so wide but about 2 inches deep and it won’t heal it seems. A lot of old skin around the hole died and has been peeled off. Also I’ve made sure it’s not infected (thank god). One more thing, I am not sure what caused the hole maybe I stepped on something… Does anyone know why it’s healing so slow and what could be the reasons?