Despite having a feeding tube installed and using it regularly, my husband lost almost 30 pounds during treatment and one month after. He, too, lives on ensure, to this day! He has some kind of sores in his mouth that make eating solid food painful! So.. Yes, watch the weight! The better supplements you can take, the better you will feel throughout the treatment.
Tom also had some minor burning on the neck. We used Aquaphor twice a day and a specialty lotion we found at Sunflowers with no alcohol and aloe/shea additives. I also rubbed lotion on his face as it tended to be dry and peeling also. Toward the end, we started using Silverdene, as well. That stuff was a God-send!! It cleared up the burns in less than a week!
Best of luck to you!!