It is possible to get tetanus from a 3 mm wound, but this is less likely. Whether or not you get tetanus does not depend entirely on the depth of the wound, tetanus in general is a possibility because of the wound. Not all wounds cause tetanus, but cuts and gunshot wounds are very likely to cause tetanus because they carry a lot of bacteria, which are difficult to remove. 3mm wounds are relatively small, and if they are properly disinfected and treated, there is no risk of getting tetanus. If the wound is not sterilized properly and is infected with bacteria, the incubation period of tetanus is about two weeks, so if the wound does not heal in two weeks and the patient is not feeling well, the patient may get tetanus. A 3-millimeter wound is generally not a cause for undue concern. If you are not sure, you can go to the hospital for tetanus toxin or tetanus immunoglobulin.