High arches make for fun floral henna feet designs ! I love doing fun henna designs in different places . The insides of the feet is a great place to put henna for the summer – you can see it while wearing flip flops, henna on the feet lasts for at least 14 days and it always gets nice and dark. Here’s the latest floral henna feet tattoo stain the next day. It will darken even more 48 hours after the henna was applied.