When experiencing breast pain and swelling while using mugwort for foot soaks, it is primarily considered that mugwort promotes overall blood circulation, which may lead to painful hardness upon touching, mainly suspected to be caused by mastitis or a tumor. It is advised to promptly visit a reputable hospital to investigate the specific cause and rule out inflammation or tumors in the breast. This can effectively prevent worsening of the symptoms. Additionally, rest is important as mugwort foot soaks can be beneficial for bodily health, but if symptoms occur, it is essential to immediately stop the treatment.