Spanish term (edited): pero me quedó viendo feo

The problem I see with the three suggestions previously offered is that none of them capture the notion of duration implicit in "quedarse + present participle." A "look" suggests an expression that quickly dissipated (and a "glance" explicitly indicates the expression in question was of short duration).

"Glared," without qualification, implies duration beyond a mere moment. If you wanted to make this idea explicit, you could write "kept glaring at me."

While all this might seem like splitting hairs, I think it a meaningful distinction, both in terms of faithfully reflecting the semantics of the original, and because of legal implications.