Hello, I can understand your concern for bite marks on buttocks area. After reading your query I can get that it is a condition known as perniosis or cold injury to the skin. It is characterized by the initial pallor and then blue patches on legs after exposing to heat more severe cases there can be more redness and even blackening of the skin. It appears exactly same as some bite marks or related issue. I suggest you to protect yourself form the cold and wear warm clothing. DO not expose yourself in front of heaters or warmers or similar apparatus directly as it can cause more aggravation of the problem. Wear double inners one over the other. Do not expose to cold environment. Additionally you can take pain killer like Ibuprofen or paracetamol two times. You can take further guidance from your family physician. All the best.