There is no contraindication to having Botox, Dysport or Xeomin when taking Prednisone. The onset of activity, duration of effectiveness and the extent of its action would not be compromised.
There is no reason to avoid Botox injections for wrinkles if you have a seafood allerrgy. There are no chemicals in the botox mixture that are known to be the responsible chemicals in seafood allergies.
When Botox doesn't "work" we must evaluate the anatomy and determine if the muscles are moving. If the muscles are relaxed and not contracting during active attempt at raising the forehead, then the Botox is working. If the lines however remain, despite the muscles not moving, then...