Hi Needlephobia Thanks for getting in touch. It not usual for someone's finger to go blue after using the lancet, you may have just hit a nerve of a small blood vessel. The blueness will only be temporary. If the blueness persists it may be worth calling NHS 111 for some advice. One thing that I can do, is to absolutely assure you that the lancet was clean when it was supplied to you. The lancets are completely sterile and can only be used once. As soon as the lancet has been triggered, the needle retracts and cannot be triggered again. The Surgilance is one of the safest lancets on the market. Over 2 billion have been used and there have been no adverse events reported. I hope that this helps to answer your question and put your mind at ease. Kind regards Gary Carpenter