It might be easier to ignore the experience, and just add 200 constitution points (then remove them after you get out). By default, the save editor offers to backup the data file before changing anything. If you made a backup, or saved under a new name before using it, try reverting to the previous version (I assume the SaveEditor backup of the data.000 file would be in the game folder '..\Divine Divinity\Run\savegames\<name>', with an .old or .bak extension).
