Student or Learner
This is a letter written to a famous author to complement her, and what does "get into the skin of every character" mean? To go deeply inside a person and understand every aspect of him or her? Is it a metaphor for "to fully understand someone"?
ex)I have read all your works and felt that you have transformed yourself into the voice of every human being to whom fate has not been kind...The weapon you have chosen to fight for human diginity is the pen. Is not the pen mightier than the sword? It is beyond me to guess how you manage to get into the skin of every character and capture the nature of each with extraordinary precision...
Yes, it would mean to understand them very well, as if you were in their place.
By the way, to complement is to make perfect or complete. To compliment (same pronunciation) is to give praise.
(not a teacher, just a language lover)