The first thing that comes to mind when you think of the word “sugar” is sweetness, but too much sugar in the blood is not a “sweet” thing. The right amount of glucose provides the body with energy, but in people with diabetes, the level of glucose in the blood is high, but it is not used effectively and can have a variety of harmful effects, one of which is neuropathy. On the one hand, elevated blood glucose can directly cause swelling of nerve fibers and neuropathy. On the other hand, high blood glucose can narrow or even completely block the tiny blood vessels that carry nutrients to the nerve fibers, and just as people become malnourished and sick when they don’t eat, nerve fibers can become malnourished and neuropathic when they lack blood supply. If diabetic painful neuropathy is left unattended, the pain will gradually worsen, and even skin ulcers that are difficult to heal will appear, and if combined with serious infection of the ulcers, amputation will be required. Therefore, early diagnosis and treatment of diabetic painful neuropathy is very important. So what conditions should diabetic patients be alerted to when they have diabetic painful neuropathy? The first to be affected are the smallest peripheral nerves in the body. Typical examples are the peripheral nerves at the tips of the fingers and toes, sometimes manifesting as numbness, sometimes with pinprick-like pain, sometimes with burning pain, and sometimes with a sensation of ants crawling. The nerve lesions can gradually progress upward, for example, from the tips of the fingers to the wrists, and from the tips of the toes to the ankles and even the knees. Some patients feel as if they are wearing socks versus gloves. There are also some phenomena in life that are cause for alarm, such as not feeling pain even when touching very hot water, or feeling pain in the tips of the fingers when holding something. These are all signs of diabetic neuropathy. It is important to seek medical attention when these conditions occur and pay attention to blood sugar control to avoid further deterioration.