Well, the reverse has a lot of legend left and looks to me like the desirable VICTORIAE BRIT reverse.
Caracalla did issue this legend, and the obverse legend supports it being him, but Ihavent found the exact issue. Take note of the IVS above the head and the spacings on the reverse.

EDIT: I suspected this was Septimius Severus, but discounted it because there isn't a beard visible, butr I think it is him:

Edited by Ben
04/29/2014 3:14 pm