Help! Hoodie neck too small

I’ve got a 7 month old and decided it was high time to finally learn how to knit. I decided to knit him a hoodie. I found a pattern and corresponding video online. I knit it and… The neck is too small! I van get it over his head but barely and he’s not a fan. I need to figure out how to loosen, stretch, cut and reseam - anything- the neck so it’s a little bigger. I’m such a novice I just don’t know where to begin. I’m heartbroken bc I’ve spend hours and hours on this. Lesson learned for next time but any way to salvage this one?? Help:)

Oh no…that’s too bad. That’s a hard one to fix. Can you tell us the pattern name and a link? It would help if we could see it/read it.

And here’s the pattern I did-

Here’s the pattern I used -

You could take out the hoodie and go back to the step of picking up sts at the neck. Check at this point to make sure that the neck fits [I]very[/I] [I]easily[/I] over your child’s head.
If it’s ok, then Instead of picking up 8sts on each side, pick up more, 10-12 sts on each side if you can. You can also use a size larger needle to do this so that the sts are looser where you pick up, then after a row or two, switch back to the needles you used to make the sweater.