Its hard to know what to put in them when we dont know your bridesmaids. Its best to give them gifts that are tailored to their taste.
I'll be honest, I would not be excited to receive a cosmetic case as a gift. I have my own makeup bag that I picked out for myself and it would end up collecting dust. But if you think your girls will love them, more power to you.
@mbecker912 since you already bought them for the girls maybe chapstick, hand sanitizer, a little thank you note, asprin also if you are getting the girls their jewlery as a gift you can put that in there as well. i say those things because even if they dont use them the day of the wedding this stuff could be used anytime..hope that helps