OK, first, dont let this happen again. You should always get off any shed before the next one, esp. on the toes. My best method is to drop a dab of mineral oil on the toe, soak the gecko in a sauna, and then use a fingernail to gently scrape the skin off. It will be hard, because my guess is the skin is constricting the blood flow by now, and it will be swollen and painful. the gecko will prob not cooperate, so you will need to restrain it. It may take several tries and several soaks, but keep trying. If you dont get it off, the toe, or at least part of it, will die. Even so, if this does happen, dont worry, it will be fine. Hopefully once you break the circle of skin and release the tension cutting off circulation, if you have got it early enough, the swelling will go down almost immediately. You can also put just a little neosporin on the toe to speed up the healing. If you cant get it off, with the next shed the tip of the toe will start turning black, and will then fall off. If that happens, just keep the stub clean and neosporin it until the scab heals. Your gecko will be fine w/o a toe.