Jealousy was a petty emotion. In their group it was reserved for Irma and Cornelia and Irma's complaints over Martin and Cornelia's dramatics and love triangles. They were both the ones to find themselves with boy drama - them and Will, who unluckily, at the minute, was not fighting with Matt. If she had been fighting with him, that would've implied she was able to find him.
Hay-Lin was not at all jealous. She was well above that.
Eric hugged both cheerleaders back and they simultaneously kissed him on the cheek.
She scowled.
Okay, so maybe she was a little jealous.