so how do i know that my baby is teething ? i feel like his is but not to sure , so he's been…

so how do i know that my baby is teething ? i feel like his is but not to sure , so he's been sticking his tongue out a lot & last night and this morning he was just crying and crying and he's never like that ever and he has to white spots like on the side of his mouth where his tweaks should be . 😭