When can I start wearing makeup over my eyebrow transplant?

Any graft site will heal after six days and the graft will be firmly in place.  You can't pull it out at this point.  The skin is healed over.  There is no open wound.  Logically, you should be able to wear any form of makeup at this point without risk or worry.  
Generalization exist in the hair transplant field such as waiting 10 to 14 days for everything.  However, this is not the case.  An eyebrow wound should be in the range of a very small gauge needle size for the placement of a single hair graft.  The wound is smaller than the size of a wound to draw your blood, which you know seems to heal over night.  

The main this you should avoid is burning the grafted area by the sun light.  

I instruct my patients to resume normal hair care of the eyebrows after a week (7 days) after the procedure, and are encouraged to gently rub off the crusts that remain after 8 days with mild baby shampoo. The hair follicle is intact by that stage and gently rubbing will not cause the hair graft to be dislodged. After eyebrows are healed in the 3 to 4th week mark is when we instruct patients the OK for makeup.
Best,
Dr. Anil Shah, MD FACS

We recommend to our patients that you can start to wear powdered makeup 2 weeks after the eyebrow transplant.  We don't recommend that you use any sticky makeup on the eyebrows. At our practice we tell patients you can gently massage the scabs with a mild soap after 1 week of surgery but we do not recommend that you exfoliate the eyebrows.

You can start wearing makeup after an eyebrow transplant one week after all of the crusts are off so that no makeup lodges behind the crusts