It’s not hair growing in, it’s more like the hair is shedding. It kinda feels different from normal hair. Anyway you can shave it if you want to, but you can also try plucking them out to see how easily they will come out. If you shave them you don’t really know if anything hasn’t been lasered and needs a touch up.
I usually just exfoliate rather than shave. My underarms were clear after a week.
Remember to let it grow out before the touch up so you know what bits need it 