I took a photo and can't erase it?

So my dad let me use his work phone (it's an iPhone) and I took a picture of my self and I didn't know they weren't synced until my sister told me and I don't know the iTunes Password… I don't know what to do

I know what you can do, learn a lesson about not using a phone to take photos you don't want getting out
once you take a pic with a phone and send it to anyone or upload to the cloud its online forever, you never get rid of it and eventually it comes back to haunt you if its a pic you are embarrassed about
try to look guilty and sorry at the same time so when your parents see the photo and confront you your chance of getting in trouble is less