As younger Ruth is getting out of her father's wagon (in which she was hiding), she has her mole on her upper right lip/cheek. After "Father" slaps her, the mole is back on her upper left lip/cheek where it has always been.
During one of the "Ruth Flashbacks", Young Ruth is located by her father in the barn. She gasps and steps back in a close up shot. The mole on her face is on the right upper lip, but in every other scene (with both young and older Ruth) the mole is on the upper left lip.