Bridesmaid help/advice!

My best friend is one of my bridesmaids, we've been through everything and she is fighting through depression, a big part of it is she self harms, with enough help and support she is getting better and has now stopped (yay) but has asked me if I can find her a way to cover her arms up (very self conscious) does anyone have any ideas of what I could buy that would look nice with the dress?