Unknown (Eastern) Roman #11 [επιλυμένο]

Hello all, 

I have a coin here that I believe is from the Crisis of the Third Century, though the emperor is hard to determine. It also looks to be Eastern Roman but I am not sure. The coin is around 2.4g and around 17mm. 

The reverse is SECURITAS REIPVBLICAE. The obverse is very worn, but maybe it's Valens? There is an 'S' after the head of the emperor, at the start of the second part of the lettering. Valens have some coins with similar structure (DN VALEN-S PF AVG).
The mintmark at the bottom is CON, but I suspect that it is incomplete.

This coin fits the bill: N#90174, but both sides have a lot of missing parts, so I'm not a 100% sure.