Slut Shaming

Hear me out, please. I know this topic has been brought up a million times, but I'm wondering how many of you have been shamed and did you speak to that person about it. I'm 40 years old and feel foolish that I've been slut shamed by my SO's mom. I opened my Facebook page and there was a message her asking me to take down my picture because it's sexually explicit. She reported the photo to Facebook. The picture was taken by a professional photographer and aside from a bit of cleavage, it's not sexually explicit at all. Now my SO is fighting with her. I don't know if I should say anything or just let it go.