Make your "come back" personal.
Give it real meaning outside of, "I want to look good naked"
While yes, that might be a good reason... but get a little more personal than that.
Remember those days you hid from the camera because you didn't want to see yourself. Remember those days where you always had to POSE for the camera or get your "good side"
Remember those days you didn't feel comfortable in your body.
Remember those days you couldn't make it up several flights of stairs without needing to catch your breath.
Remember the pain...
Use that. Use those feelings of hurt or helplessness and make that promise to never feel that again.
Then remember, I am here to support you!
And never forget, you ARE WORTHY