Straighten your arms and lift yourself off of the floor.
I have a similar problem.
What they have in common is eating healthy and working out hard! A few times I have found joggers with the right cut that skim my hip area and those are great but sooooo hard to find.
The thing is that this muscle is really hard to target since is a pretty small one.
I think that because of the minimal cover in the hip area, it makes your hip dip look much more obvious.
The number of people having no hip dip, or very prominent hip dip, is probably going to be the minority.
I started dieting and hating on my body, but they never disappeared.