I Have Uneven Eyebrows, Will Botox Fix This? (photo)

While the injection of botox to the outer fibers of the orbicularis occuli muscle of the left side can result in elevation of the left eyebrow, the degree of elevation would be unpredictable and may not match the right side consistently. It would seem the right eyebrow is elevated to compensate for a mild ptosis. If you feel compelled to do something about this situation, a consultation with an occuloplastic surgeon would be good starting point.

My eyes were immediately drawn to your scar in your photograph. Upon enlarging the photograph it is apparent that there is a contraction of tissues creating soem contour irregularity.  The contraction of the healed wound when you were younger has pulled up on the outer corner of the eyebrow. You have lost the normal mid eyebrow elevation of the arch and the scar pulling gives you a slight  "stern" appearance by raising the corner of the eyebrow.  You have less redundancy or "hooding" / blepharochalasis of the right upper eyelid than the left because of the right eyebrow lift.

I don't think botox will help relax the scarring in the tissues or relax the muscles of the right forehead to lower the right eyebrow.  You could have a scar revision with a "Z-plasty" to lower the corner of the right eyebrow and if hooding then occurs, you could have a blepharoplasty (eyelid tightening) on both sides.

The reason the eyebrows look similar when smiling is because you use both the eyelid and smile mouth muscles when smiling and the periorbital eyelid muscle, when contracting, encircles the eye and the outer component pulls down on the outer corner of the eyebrow (that's why we inject that area with botox off-label, to help give a lift when needed). 

Notice how the right upper eyelid is just a bit heavier than the left upper eyelid.  The right upper eyelid margin hangs into the cornea about 1 mm more than the left upper eyelid sits on the left cornea.  To compensate for this, the forehead muscle is working just a bit more on the right side than on the left.  This most likely accounts for the difference in appearance.  BOTOX might help balance this.  However, I recommend being assessed by an oculoplastic surgeon to determine you best treatment options.