My question is basically the same question as this one previously asked:
How to continue lines on next page in exam class \fillwithlines
Except its for \fillwithdottedlines
"I use the exam class to typeset my exams. I usually leave space for answers with \fillwithdottedlines{3in} because I prefer to fix the amount of space. However, when a question is at the end of a page and the space required by \fillwithdottedlines{3in} exceeds it, the lines do not continue on the next page. Instead, the entire question is moved to the next page while the current page is blank space. Is there a way to change that behavior and have lines starting on one page and then continue on the next."
Any help would be appreciated :D.
\begin{document}
\begin{questions}
\question This question should appear on page 1. It should be followed by lines which continue on page 2.
\fillwithdottedlines{20in}
\end{questions}
\end{document}