Use of the recall stone would not lock you out of Charwood. However, completing the main quest would.
The main quest requires that you submit 2 of the possible 3 quest items. Once you have done this, the chapter is finished and you are expected to proceed to the next chapter (Luskan).
If you wish to complete the Charwood area, then you must reload a save game from before submitting the second item. That or use the console to alter module variables. I can't help with that.