How does Jekyll change physically and mentally throughout the novel? Other then not being Hyde how did he change?

First, an almost invisible change: he starts planning for possible negative fates. That is to say, he makes his will and gives it to Utterson. He knows things might go wrong. A second change: he goes ahead with his experimentation anyway. When Utterson sees Jekyll in Part 2, Jekyll looks "deathly sick" and carries himself with a "feverish manner." Both of these are changes in body (and the second a change in mind). In Part 3, Jekyll loses control of his fate (also body and mind, to Hyde); this means he is now at the mercy of others. Finally, though, he becomes responsible: forcing himself into a situation where he'd be punished for his crimes (as Hyde).