I have no experience with this, but that sucks to hear! Would it be possible to have some sort of "makeover" or try things with your hair/glasses/jewlery to look more how YOU like it? Like, accentuate cheekbones or frame hair? Maybe only temporarily to get a feel that your face doesn't always look a certain way. I just grew a beard and called it a day, so I'm no expert.
In a counter thought, would radical acceptance help over radical positivity? Like, I don't enjoy that the left side of my body (hands, feet, etc) are ever so slightly larger than my right. I can't change that, I don't really like it, but I've been living with it all my life, and I accept it, even if I would prefer it differently. I got more important shit to worry about, like friendships, my dog, and enjoying other things.
Yeah, I remember it and don't like it, but it's not "me"... or at least not a large part of me anyway. Yeah, faces are important, but it's the person behind the face that matters to me, and I hope you have people in your life who are similar. People have fat on their faces, some more, some less, and I don't think any less of you for having face fat. I also don't think any less of you for worrying about it. It's an important concern for you!
As a last thought edit: Maybe you could spend time enjoying parts of your face that you like, like your eyes/eyebrows/hair?