The hairy part of the big foot and thumb is often red and swollen, and it hurts when touched! Especially when walking, socks will hurt when rubbed. What's going on here?

Look for pus and smelly feet. If so, it should be paronychia.

If it's just redness, it should be just bacterial infection. This is also the case with my big feet and thumbs in recent months. It hurts when you touch it, but it doesn't hurt when you walk away. Later, I insisted on washing my feet with hot water every day, and if possible, I soaked them in vinegar, because vinegar can sterilize or wash them thoroughly with shower gel or something. The purpose is to kill bacteria. Pay attention to keep your feet dry after washing, remember to wash them every day, and pay attention to the ventilation of your feet on weekdays to prevent bacteria from being organic.