Conversation so far:
How did Erich Honecker get back into politics?
Honecker befriended Walter Ulbricht, who had not been aware of him at that point.
What did Walter Ulbricht have to  do with it?
Honecker sided with First Secretary Walter Ulbricht, despite the majority of the Politburo attempting to dispose Ulbricht in favour of Rudolf Herrnstadt.
Did his return go smoothly?
Honecker himself though faced questioning from party members about his inadequate qualifications for his position.
Did he remain in office?
On 27 May 1955 he handed the Presidency of the FDJ over to Karl Namokel, and departed for Moscow to study for two years.

Question: What did he study?
Self-contained rewrite: What did Erich Honecker study after leaving politics?