"Prometrium is prescribed for postmenopausal women who are taking estrogen (hormone replacement therapy); it prevents a buildup of the lining of the uterus and abnormal bleeding. Prometrium also may be prescribed to restore menstruation if your menstrual periods have stopped.
Prometrium increases the risk of blood clots, which can lead to phlebitis, breathing problems, vision problems, or stroke. If you experience any symptoms that might suggest the onset of a clot-related disorder--pain with swelling, warmth, and redness in a leg vein, coughing or shortness of breath, loss of vision or double vision, migraine, or weakness or numbness in an arm or leg--stop taking Prometrium and see your doctor immediately." (Drugs.com)
I might call the doctor and let them know about the warming sensation, just to be careful. I hope that it is a

Make sure you kup!