Black blood blisters after freezing of plantar warts is a normal phenomenon, the most common method of treating plantar warts is to use liquid nitrogen cryotherapy, which often results in redness, swelling, blistering and drying of the affected area after treatment. The most common method of treating plantar warts is to use liquid nitrogen freezing therapy, after which the affected area will be red, swollen and dry. Metatarsal warts after freezing black blood blisters, usually due to the local freezing is too heavy, local subcutaneous tissue fluid oozing caused. It is usually not necessary to deal with, can be self-healing. It’s best not to pick the blood blisters yourself to prevent infection. If the blood blister is large and affects normal life, you can use a sterile syringe needle to puncture the blood blister and draw out the fluid. After extraction, you can apply some local povidone-iodine to sterilize and disinfect, however, it is not recommended to operate by yourself, it is better to go to the hospital through the general surgery operation to extract the fluid, so as to avoid operating errors by yourself.