i was hiking with shoes which was the same size of my casual shoes, i asked my fellow hikers, they said i should've bought shoes with extra inch or 2 for protection. (im not sure if this is reasonable? coz extra inch or 2 in shoe size is not comfortable when walking/hiking?)

EDIT: i actually took a look at the green toenail (by lifting a little bit), the green thing is sticked to the toenail, not to the skin.. so im fine.
(same as my black toenail, the black thing was sticked to the nail itself, not the skin.