Suspected Facial Nerve Damage, Left Side Cheek Bone? (photo)

The photo appears to be an inverse image, because the described weakness is shown on the right of the photograph.  The photograph appears to show partial motion of the involved cheek, decreased fullness of the cheek, flattening of the nasolabial fold and upper lip; these findings are suggestive of an injury to the zygomatic branch of the facial nerve.  Although I agree with previous posters suggestion that you see a Facial Plastic Surgeon or Plastic Surgeon that specializes in facial nerve injury, partial motion after two years is unlikely to be improved upon by surgical intervention.

I am sorry this happened to you.  There are two major things going on in your photo/question:
1) The photo is flipped (I am assuming you used an iPhone, which can flip selfies).  Nevertheless, based on what you said, it sounds like your cheekbone was fractured.  Fixing this is done in one of two ways: a) cutting the bone and moving it back to the normal position or b) placing an implant to "camouflage" the real position of the bone.
2) The nerve is likely injured.  A cheekbone fracture classically runs over to and involves the opening in your cheekbone where the nerve for sensation to the face emerges from the bone to supply the sensation to your cheek.  Many times this nerve will be numb for a period of time and then the sensation will come back.  Nerves usually improve over a period of two years and once they reach that time point they often plateau.  There is the chance that by decompressing the nerve at the same time as option a or b you may get sensation back, but I would not count on it.
I would recommend you see a Board certified plastic surgeon with a specialization in Craniofacial surgery to evaluate you and help guide you through this process.

The posted photo does demonstrate facial asymmetry and left malar flatness. Also facial nerve paresis is shown. Best to seek in person evaluations via PS, ENT, Oral surgeons - some doctor. 

You need to seek consultation from a plastic surgeon who is a "craniofacial surgeon."  These surgeons are usually at major university medical centers have extra expertise in complex matters like yours.  It apprears likely that you broke your cheek bone and as it was untreated, you have a deformity from that.  Repain can be done but is very complex, and the nerve damage might well be uncorrectable.