According to your description, it is fire-induced erythema, which is really caused by long-term use of hot water bottles. Other reasons include warm fire (often in a fixed direction), hot feet, electric blankets and so on. Because of different habits, the parts are different, and the calves, thighs, feet and back are the most common. It is characterized by reticular red or brown spots, which are neither itchy nor painful.

Most bad habits will disappear naturally when they stop, and no treatment is needed. If it doesn't subside, you can consider laser treatment. Red is generally effective and brown is generally poor.

Yang Xichuan, Department of Dermatology, Chongqing Southwest Hospital:

Treatment is quick, but the cost depends on the size of the area, and most of them need multiple treatments. It is recommended to go to the hospital to see if it is suitable for treatment before making a choice.