May an ice bag wrapped in a towel be placed on swelling 6 weeks postoperative mastectomy with DEIP for aching?

In the area of the mastectomy skin (native skin) the sensation is different, and so indeed any ice or heating pack to the area might potentially cause a burn in the area and so would be careful- alternatively I am not sure ice will change the underlying sensation and so would ask your plastic surgeon for options... best of luck..

Dear lkt,
I agree with the other posters. First and foremost, you should check in with your surgeon. It is common to have post-mastectomy neuralgia (pain) where the mastectomy cut the nerve endings. Steroids and nerve pain medications may be all you need, spending on your in-person exam. I am not advocating ice, but, from a physiologic standpoint, you are unlikely to hurt the flap with ice. Enough additional blood connections have been established that what you see, flap-wise, is there to stay.
I really hope this helps and that you feel better soon!

I'm sorry that you're going through postoperative complications.  Your surgeon needs to address the source of the pain.  You may have areas of fat necrosis in the DIEP flap adherent to the muscle underneath that are causing the muscle spams manifesting as pain.  Consult with your PS to make sure your pain control is opitimised.  If there are no surgical causes for the pain, your pain needs to be optimized medically.  Good Luck and I hope you found this to be useful.  
Ali Sadeghi MD FACS
Breast Reconstruction Specialist