Thank you for your question.How much of the fat survives during a fat transfer is highly variable and is dependent on several variables including surgeon, surgical technique, technique of fat grafting, health of the patient, and post-operative compliance by the patient. Extreme heat/cold compresses are usually discouraged post-operatively as they can cause burns on the patient without the patient being aware because the skin in the surgical area is usually numb immediately post op. We usually provide our patients with a detailed outline of recommended post op instructions that we have found help encourage the maximum amount of fat survival. Your board certified plastic surgeon should be able to provide you with their recommendations for your post-op recovery.Good luck with your journey!