moh dying hair bright pink

I would sit her down and tell her you fully support her dyeing her hair...after the wedding. I would offer to work with her to find another stylist who has availability after the wedding. It does sound like she booked this in advance and just didn't tell you, which is pretty crappy.

I understand her desire to do this - I would love to try frosty blue hair - but someone else's wedding where you are a BM is just not the place to do this.

FWIW, if she has dark hair, it will not come out bright pink if she doesn't bleach it first. Which means it might be barely noticeable, or it might look horrible.

You handled it way better than I would of had.

Personally, I would say something to the affect of that you've known her as a redhead and want to look back on your wedding photos years from now and see her how you've always known and loved her (with her natural red hair). If she dyes her hair all the time this may not be as convincing though, but if this is an unusual "going bold" move for her I think asking her to wait is fine. In the end the most you can do is ask her to consider waiting until after the wedding to dye her hair, but emphasize that you love her and want her there no matter what and ultimately its her decision.

If I were the friend I would respect the brides wishes and wait, especially since it would only be a few days difference. Waiting a week to dye my hair would be totally worth it if it made my best friend happy.

You handled this really well, but I'd be really worried about her damaging her hair. Also never would I put getting to have pink hair at work for a month above my best friend's wedding, but to each their own.

You did good. Hopefully she does too!

Can she do an updo so it’s not all out?

That’s really annoying and a reason I’m not having a bridal party.