I Just Had Double Eyelid Surgery but Why Don't I Have a Crease? (photo)

It looks like you still have some swelling that could be hiding your results. It's best if you wait a few more weeks for the swelling to subside before you assess your results. 

No, the crease should not necessarily be present only a week after surgery. As the swelling goes down, the crease will become more apparent, little by little

I do agree that things look a bit rough and your concerns are appropriate.  However, it is probable that you did your homework and had every good reason to but your confidence in this surgeon.  I recommend patience at this point. It may be that your surgeon did not establish a strong enough attachment between the crease and the underlying levator aponeurosis.  This would prevent an solid crease from forming.  However, this will become very clear over the next 6-8 weeks.  If the crease does not form itself during this time, consider reposting photos here. 

If you had fat removal and no crease before double eyelid sugery, its unusual not to see any crease afterwards. If you didn't had fat removed but just had multiple poorly-defined creases before surgery, then it is normal to no see the defined crease until swelling resolves. Communicate with your doctor to understand what's going on with the healing after double eyelid surgery.