Cardiovascular surgeon at the First Affiliated Hospital of Tsinghua University: Generally speaking, antibiotics for dengue should be used for at least 2 weeks, and should continue to be used for 1 week after the redness and swelling subsides, otherwise it is difficult to cure and easy to relapse. The cause is usually nail fungus, most of which is caused by gouging the nail groove inside the toenail of the big toe. The solution is not to cut the toenail too much, let it grow longer than the nail bed, and the nail fungus will naturally heal. There are also fungal infections of the foot (foot fungus), so during the use of intravenous antibiotics, you can use potassium permanganate solution 1:8000 soak feet for 15 minutes / time, once a day, that can control the nail infection and can control the fungal infection.