VTG 60s Mini Dress

This vintage 1960s dress is so cute and the embroidery is amazing. Since purchasing it has one small stain on the back (pictured). It's not noticeable unless you're looking for it (perhaps it was even there when I got it). I have not tried to wash it out. I'm always so nervous about washing vintage clothing. Purchased on Etsy for an event and have not worn it since. Feel free to ask questions!