Is it normal to have acne on cheeks after rhinoplasty? What about increased mucus?

As far as acne goes, the only reasons I can imagine would be the cause is if you didn't wash your face after surgery because of the cast or a reaction to whatever was used to clean your skin at the time of surgery (usually betadine). If your surgery was 4 months ago; however, I would not think that either one would be an issue at this point. I usually only see a pimple or two on the nose after surgery if anything because of clogged pores underneath the tape and cast. It usually resolves quickly. Your's would be a unique situation, so you may want to see a dermatologist to assess your skin in person. 
Mucous in the nose can be increased or decreased after rhinoplasty. It will go back to normal with time. Sometimes it can feel like there is more since dried mucous can get stuck on the incisions inside the nostrils. In addition, it has been a really bad allergy season in central Texas, so it could be the mountain cedar that seems to have come back with a vengeance. Whatever the reason, you should rinse your nose once or twice daily with Neil Med sinus rinse (with distilled water) followed by flonase once a day to dry up mucous. You may also want to use AYR gel with aloe in the front of your nostrils  if it gets too dry.
I hope this helps!
Sarah Saxon, MD