I'd freeze the leftover comfrey, and put it on bruises, any time you want something cold.
Creating Permanerd Comfrey Salve
Comfrey has amazing healing properties. In this video you will see how I make a salve from this magical plant using comfrey, olive oil and beeswax
https://blossom.primal.net/538f460c84807ca0193b4e3d52cb571696e3e98cf6ba0e0be5c76848cc0507db.mp4
Discussion
Great idea. I have frozen pultices using water and comfrey.