Directions to use:
Poultices
 to help heal swellings, inflammations, and sores. To make such a 
dressing, let the leaves mush up in hot water, squeeze out the excess 
liquid and wrap several handfuls of the hot, softened foliage in a clean
 cloth. Apply the pad to the affected part – comfortably hot, but not 
scalding–and cover the area with a thick folded towel to keep the heat 
in. The moist warmth enhances the healing effect of the allantoin.
Safety precautions:
Don't
 apply Comfrey to broken or damaged skin. Doing so might expose you to 
large amounts of the chemicals in Comfrey that can cause liver damage 
and other serious health effects.