I Botox on my forehead about 15 days ago, my eyes look inexpressive and lifeless... is this normal?

Thank you for your question about botox.  Botox does not start working for at least 10-14 days post treatment.  However, the benefits should last 3-4 months.  The amount of units needed differs from person to person.  I would recommend following up with your provider to make sure you do not need any touch ups.   It is difficult to know for sure what you may benefit from without an in person consultation.      
To be sure, see two or more experienced, licensed and board-certified providers in your area for a complete evaluation to make sure you are a good candidate and that it is safe for you to have treatment. I hope this helps.

Spiritless eyes is very disconcerting, but without a picture, I am not sure exactly what effect you are trying to describe with inexpensive, lifeless and spiritless. . You should definitely contact your Botox provider and let them know about your concerns. In rare cases, Botox administered in the brow area can spread to adjacent muscles and cause something called Ptosis, which looks like a droopy eyelid. Botox can also cause the brow muscles to push down onto the eyelid space, causing the eyelids to look heavy. These side effects are rare, and  dissipate as the Botox wears off.