It is understood he requires steel plates to be inserted to put his shattered jaw back together.
"Jaw in bits, time for more plates to go in to put it back together like a jigsaw," Rogan said on Twitter on Monday morning.
"By the time I get this other operation done, I will have more plates in my face and neck than we have in our cupboards."
Rogan also indicated that it may be time to hang up the gloves.
Thanking everyone for their well-wishes, he added: "Have had a great career - out with a bang."
At 42, the former Prizefighter champion had 11 years on his opponent Teper.
Their clash in Germany was Rogan's first bout in nine months, after he enjoyed a win over Czech boxer Ladislav Kovarik on the undercard of Carl Frampton's European super bantamweight title challenge against Kiko Martinez back in February.