What type of bite looks like a little hole in your skin?

Various bugs if itch. Various bugs can leave a tiny, almost invisible, hole in the skin. The bite area should be a bit raised, into a welt. It should be itchy and a little reddened. If there is a tiny hole in the skin with no reaction around it, it may just be a skin pore plugged with a comedone (a clump of old skin cells), which is fairly common and is one of the causes of acne.
Arthropod Assaults. There are many bugs which love the human skin. One of a dermatologists most important tools is his eyes. That means that it is necessary to see these spots to make a diagnosis of what actually happened to the skin. Some bugs or arthropods as we call them, actually do leave a mark in the skin, but again it's necessary to see the patient.