The phrase "after a paragraph" is correct and usable in written English.
It can be used to indicate a point in time or a sequence of events that occurs following the completion of a paragraph.
Example: "The author provides a summary after a paragraph to reinforce the main ideas discussed."
Alternatives: "following a paragraph" or "subsequent to a paragraph".
You are now reading this, though after a paragraph like the above you may be fewer in number.
After a paragraph break, a little injection of white space, she continues: "I saw him shaving with his hat on".
I knew that that wondeful description of Mr. Pumblechook appeared on the bottom half of a right-hand page, perhaps 10 lines from the bottom, and a few lines after a paragraph break.
I'm perfectly capable of scrawling a shopping list but last time I was required to write a proper letter, my hand ached after a paragraph and after a page my whole arm started to seize up.
after a paragraph in p6, a question mark after some phrases at the bottom; instances as response to student's "the opposing sides and their points were shown with supporting details".
After a paragraph of glowing detail about this fellow's abilities in molecular lab techniques, his boss closed by saying that "John was a continual influence on all those around him".
V. S. Naipaul says he can tell if a writer is female after reading a paragraph or two.
The prose that describes Swann's sexual obsession, for instance, is so good you have to stop after many a paragraph, re-read, think over it.
The fractured technique of the piece, which starts over 41 times, often after only a paragraph or two, is on one level a parody of Salle's own violent juxtaposition of images.
After reading a paragraph that described the Fair Elections bill, voters listened to messages online, moving their cursors, second by second, up if they liked what they were hearing and down if they didn't.
Republicans and Republican-leaning independents, after reading a paragraph on some projected negative consequences of climate change, became more opposed to governmental action on the issue, less willing to take personal action, and more sure of their opinions on climate change compared to unexposed participants.
