Henna at Work

I'm a nurse and Jewish. I just did this henna design on my left hand/lower arm during Chanukah and forgot about eventually going to work with it on. My husband says not to worry because it was used to celebrate Chanukah and I shouldn't get in trouble for my religion. I work in a very small and old fashion hospital where they like to make women change their hair color back to a natural type color if they go get an unnatural color put in. (just an example) I've never seen a reaction to henna or something similar to what I have. Does anyone have any advice/comments on this? All would be appreciated.