Ragnar's eyes were closed off. He couldn't feel anything as his mind was exhausted due to severe mental and physical exhaustion. Self-Heal could handle physical injuries, but mental injuries and exhaustion were difficult. The process was similar to the previous ones. His entire body was destroyed and then recalibrated to the peak possible condition. The bones, muscles, channels and many other things were also changing.
The change was once again fundamental, and it followed teh same steps. The first one to be reformed was teh outer skin and then the skeleton, followed by the vessels, and ultimately the tissues( Organs). The sheer energy consumed in the process wouldn't be sustainable if it were elsewhere. But the tower, during its existence, has been absorbing and converting the energy for a long time.