There is an old drag trick that *definitely* help with hiding stubble.
It all depends on how dark your stubble is. If it's brown or black, try using an orange powder to cover it up before putting on your concealer. If it's light (like mine), I use a white powder before putting on the concealer. The powder underneath serves as kind of a backup mask, so that when you put the concealer on, your stubble's invisible.
Hope that helps! <3