If chilblain is regarded as a chronic affection generally due to the action of cold, frostbite may be regarded as an acute affection due to the action of cold.Handbook of Therapy Third Edition. Oliver T. Osborne. The Journal of The American Medical Association, Chicago. 1918.
I picked this
To summarize... . Frostbite is a problem of degree. Mild frostbite slows the circulation of blood in localized areas (fingers, ears, etc.) which turn bluish and lose feeling. Acute frotbite, occurring when exposure to extreme cold is prolonged, slows the circulation in larger areas (hands, arms, etc.) to the point where "the entire part becomes congealed, and freezing and gangrene result."
Restore circulation in mild frostbite gradually by "laying the patient down in a cold room," covering him, and give him hot tea or coffee. Rub the affected body part with snow or rags wrung out in cold water.
Sorry to have to be the one to tell you this, but if you're suffering from acute frostbite and gangrene has already set in, "amputation is necessary." If gangrene hasn't yet set in but the patient appears to be on the verge of a coma, employ artificial respiration if needed and continue "for a long time, if necessary."
(In case you are wondering, chilblain is an inflammation of the hands and feet due to excessive cold and moisture.)
DISCLAIMER: I am not a doctor. I am only quoting from a