High blood glucose from diabetes causes two problems that can hurt your feet:
Nerve damage – One problem is damage to nerves in your legs and feet. With damaged nerves, you might not feel pain, heat, or cold in your legs and feet. A sore or cut on your foot may get worse because you do not know it is there. This lack of feeling is caused by nerve damage, also called diabetic neuropathy (ne-ROP-uh-thee). It can lead to a large sore or infection.
Poor blood flow – The second problem happens when not enough blood flows to your legs and feet. Poor blood flow makes it hard for a sore or infection to heal. This problem is called peripheral (puh-RIF-uh-rul) vascular disease. Smoking when you have diabetes makes blood flow problems much worse.