Harriett Gordon spaketh...

At this point, I've sanded back down to the stained surface. And am
wondering what to do next. Can I stain again & apply POLYURETHANE?

Here is how you can salvage the table... Sand the top down to bare wood and
restain, allow to dry thoroughly, apply a coat of blonde shellac and allow
to dry, then reapply lacquer. The shellac will seal the oil stain and
prevent the wrinkling.

Shellac can be bought off the shelf as a liquid, mix the shellac 1:1 with
alchohol before applying.
--
McQualude