Can I use a meeple the turn after begging?
Per the second edition rules:


  During the worker placement phase, players take turns placing their workers on board locations and
  executing their effects.


This makes it clear that workers "on board" are used. It never mentions which board, so that would imply that workers placed on any boards are used, and cannot perform other actions.

Also note that your "worker supply" is placed off to the side of your player board, and never directly on it. (A lot of people like doing that, hence why the "lay the worker down" language was added in the second edition rules, but officially unused workers are not on any sort of cardboard.)

The spirit of the game rules is that begging is a last resort option for someone who needs food but does not have access to it via the normal methods. It's not supposed to be an "extra" loan, and especially not to pass ones turn (which in very rare cases might have strategic value!)