Gas at night

Sorry it's a long post.

So first let me explain my son was sleeping through the night. He was sleeping six to ten hours straight until he started his three month growth spurt. Ten days straight of him nursing every two hours even throughout the night. Since the growthe spurt ended he wakes up every two to 4 hours and is fussy. Sometimes I can just carry him around and lay him back down. He'll go to sleep. If it's been a long time then I'll nurse him back to sleep. A lot of times, I need to give him a little gripe water and he goes back to sleep. My mom suggested I try and leave him when he fusses let him try to go back to sleep. It worked a couple of times, but he sleeps in the pack n play in our room. My husband gets up at four for work so he needs to sleep. He's not gassy at all during the day, but he sucks and eats his hands so much because he's teething. He's almost four months old. What should I do?