Is my Disfigured Face a "Common" Botox Occurrence? Or the Result of an Inexperienced Injector? (photo)

This is not really that common.  It also very much looks like your were treated with more BOTOX than you are being told.  21 units is a fairly small dose.  You were really flattened by your treatment.  It is possible to have the treatment rebalanced.  You can research my micro droplet botox treatment to learn how this is done.  This will wear off but it can take months and treatment results like this mess with facial feedback and can cause feeling of dysphoria and depression.  Please stick with physician and surgeon injectors in the core aesthetic specialities: dermatology, plastic surgery, facial plastic surgery, oculoplastic surgery.

The after photo is a bit hard to figure out, but it appears that you have not only a severe bruise but also really lowered brows.  I would disagree that this is a common side effect of Botox.  I have never seen anything like that from Botox or Dysport.  I would tend to blame technique over the amount used in this case.  21 units is not really an excessive amount for the "frowner" muscles.