Can a 3 almost 4 month teeth?!

Cate

I think my 3 almost 4 month is teething!! He keeps putting his hands in a fist and sticking them in his mouth and trying to bite them (this is new behavior) he’ll also stick his thumb in his mouth and bite it. He’s crying soooo much now. Not wanting the bottle nor paci sometimes. I was looking at his gums and the back ones are whitish. Is this teething? If so, what can I do or buy for him to be at ease