Teething???

Penelope • 21, & FTM to my beautiful girl born 10-27-17💕

My daughter is a little over 4 months old and lately has been sucking/chewing on her bottom lip and cooing while doing so...is this due to her beginning to teethe? She’s definitely been gumming everything and has been slightly fussier. Anyone else’s teething baby do this with the lip?