Was my Botox over diluted?

It's difficult to answer your question without having seen exactly what was done.  I would say it would be unusual to put the Botox back into the saline vial, but perhaps that particular doctor has a different way of storing the Botox.  You could just wait a week and see what sort of result you get, then contact the doctor if the result is not what you expected or contact the doctor now and tell them what you saw and ask if it was diluted correctly.  If the same number of units were used, the dilution may not really make much of a difference in the result.  

Botox and the dilution is a standard procedure.  If you are concerned that the nurse may have improperly diluted the Botox you should contact the office immediately.  If your results are not as expected after two weeks then there should be new Botox injected to you at no cost.

I think that you should call the doctors office and express your concern. It is possible that the Botox might work but may wear off too soon if not enough. If you show up in two months with this story the nurse might not even be around. Have them document your concern but wait before doing anything as you might be fine