A very large pus and blood bag on the inner thigh may be caused by boils or carbuncles, canker sores, folliculitis and other skin infections, which can be treated by medication, surgery and so on. 1. Boils, carbuncles: acute purulent inflammation caused by hair follicles and their deep surrounding tissues, can be applied externally with mupirocin ointment, can also use penicillin, cephalosporin and other drugs for treatment. Severe abscesses can also be treated by surgical incision and drainage. 2. Dengue: most of them are acute infections caused by B hemolytic streptococcus, which can be treated with antibiotics such as penicillin, erythromycin and ofloxacin. Surgery is usually not necessary. 3. Folliculitis: Inflammatory diseases mainly involving hair follicles, you can use povidone-iodine to carry out local antibacterial, topical mupirocin ointment, fusidic acid cream, etc., but also oral cephalosporin, fluconazole and other antibiotics for treatment. A large pus and blood bag on the inner thigh is recommended to consult a doctor in a timely manner, after clarifying the cause of the disease, symptomatic treatment under the guidance of the doctor, the use of medication please follow the doctor’s instructions, do not self-medication.