I was going to leave the mistake, but when I got to about the end of the cowl, I realized that while it would fit around my shoulders, if I decide to wear it like that, it's really, really stretched out.
I kind of blocked it in the hotel bathroom (I'm traveling again, Tennessee this time) and I'm not happy with it. I think I'm going to increase it to 120 stitches and re-knit. I have to finish this sweater by the end of the month, so this is a bit of a major setback. I am not happy, but hopefully I'll enjoy the final product if I fix it now.