。
Even a rare guest gets on your nerves after three days.
Literal
Rare-guest [even-も] 3-days stay-[if-ば] nose [to-に] sticks.
A ことわざ (proverb). 珍客 (ちんきゃく/ちんかく, 'rare/unusual guest') + も ('even') sets up the concession. 鼻につく (はなにつく, 'to get on one's nose' = 'to become annoying/tiresome') is the idiomatic predicate. The ば conditional gives it proverbial universality: 'if X stays three days, then Y.' This is a variant of the widespread proverb about fish and guests spoiling after three days — compare Benjamin Franklin's famous version.