Can paging be done without "next" and "back" buttons?

Also, I need the "Next" button NOT to advance after an incorrect answer. Is that possible?
Can paging be done without "next" and "back" buttons?

It is not possible to have multi page form without using page breaks (next and back buttons). If you want to prevent your users to go to next page of your form if answer is incorrect you can use conditional logic to hide/show fields and you can set your condition to show next button only of answer that your user entered is correct. 

How to Show or Hide Fields Base on User's Answer

You can also group your questions under Form Collapse field if you do not want to use page breaks. You can then also hide multiple fields at once.

Show or Hide multiple fields at once using form collapse tool

Hope this will help. Let us know if you need further assistance. 

Aha!! If incorrect then hide page break :)
I think I've got it now....