In addition to internal bleeding, with any dirty puncture-type wound you run the risk of anaerobic bacteria being left behind to cause deeper infections. Tetanus & gangrene are examples of infections caused by anaerobic* bacteria. (*that is, bacteria that thrives where no oxygen is present, as in injured tissue where no oxygen rich blood is flowing- the opposite of an "open wound" that bleeds & drains freely) In general, these type infections can usually be fought with the "right" antibiotics, but sometimes that's easier said than done, especially for our pet snakes.