What forms this pad on the side of the face?
That padding is apparently from a prominent zygomatic arch also known as high chickbones (pictures).

The bones between the eye, nose and ear are: the zygomatic bone below and behind the eye, the zygomatic process of the frontal bone above/behind the eye and the zygomatic process of the temporal bone, which extends toward the ear canal. It makes sense that when the zygomatic bone is more prominent, the zygomatic processes of the connecting bones will be also more prominent and appear as high cheeks.  



Image source: Wikimedia, CC license

Here's the photo of Abraham Lincoln from the Wikipedia's article about zygomatic bones:

 

A Youtube video The Zygomatic Bones and Ogee Curve