I looks to me like he needs some hydration ... Try bumping his humidity up to about 70% you can must his enclosure but if you are going to mist, it is important that his temperatures inside his enclosure are on point. If the temps are not spot on then you can give him a humid hide over his warm side of the enclosure ... This should take care of or at least help his saggy/wrinkled skin. .... As far as the feeding goes .... If properly thawed out and warmed up, it should be very easy to grab the feeder by the head with a thumb and finger and use the other hand to stretch out the feeder into a more natural position before offering it to him