Here are my clues for this one: he has a small, youthful-looking bust that is pearl-diademed, and because of the small bust I believe the legend on the obv is an un-broken one. On the reverse, I see Victory holding two wreaths. With these, I got either Theodosius II or Valentinian III as the emperor on my coin, with CONCORD-IA AVG" on the reverse. I quickly eliminated Val III since the coin didn't look crude enough, so all that was left was Theo II. Does anyone else think this looks like a Theo II?
It is 14 mm wide.

Also I think I see an M in the exergue, but I am not 100% certain it is one.