Samantha Pleet watercolor shirt dress

Super cute small designer Samantha Pleet shirt dress. There is a small discoloration on the right armpit that I’ve tried to photograph. Because of the watercolor pattern it’s difficult to notice (I had to keep double checking when photographing that it wasn’t just part of the textile pattern). Size 6 but fits more like a 4 imo? Dress has been living in the back of my closet and needs a good steam but is in otherwise good condition! Price is reflective of small discoloration!! Ps I haven’t tried to remove it but bet you can?