what to do if by mistake i miss a page while reading the Quran

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

You don't have to go back and recite the page that you forgot, even if you skipped it intentionally. So, it is permissible for you to continue reciting without going back. However, it is more appropriate for you to go back and recite it.

Allah knows best.