There is a good article on engorgement in LLLs Breastfeeding
Abstracts  August 1991  by Linda Shrago  ( one of my heroes
or should that be heroines )

The article that may be helpful :  Michlovitz, S. L. and S.L.Wolf
"Thermal Agents in Rehabilitation "  Philadelphia: F A Davis Co 1986.

Ruth Bacon   IBCLC  Thornhill Ontario