You get a sterile abcess with liquid nitrogen. The blister lifts the wart, blister pops and it heals eventually. The redness you see is almost certainly due to inflammation that is part of the normal healing process. I never use it, because you cannot control the depth of tissue destruction and potentially get a scar. A wart, being a non-malignant viral process, does not penetrate the Basement membrane, which is a layer in the skin. If you do not violate the BM, no scar. If you must lanceit, wash it with antibacterial soab for at least a 30 count first to reduce chance of infection. Once the tissue sloughs off, dress with antibacterial cream/ointment and keep it moist, it will heal much more quickly.