I was spraying some Ortho Weed-B-Gon Max on my lawn, and some of the mist/over-spray got in and around my flower bed (on flowers).
Are my flowers doomed, or is there still hope that they will live on?
There are a lot of factors - species, amount of exposure, etc. There's a good chance some will survive. Whilst killing ivy with this, I managed to kill the ivy and a small elm tree (the tree should not have had over spray, but perhaps surface roots did) - but cacti and some lawn weeds in the area survived just fine!
If it is a concern then I would try to wash the overspray off the leaves and stems as soon as possible. If it was a few hours ago, it might be too late - I've seen clover respond to the Ortho weedkillers in a matter of hours.