I have skinny legs but a moon face- how can I lose weight on face?

Not possible. You cannot spot reduce fat. You can firm up locally, but not lose fat, without losing fat everywhere. You need to maintain a higher protein intake, but avoid useless calories, maily sweets and starches. However, you need to avoid high calorie fats!
Lymphatics. If you have skinny legs with moon face - you must either have fillings in teeth or must have high steroids either xenobiotics or estrogen high conditions like issues with adrenals, or pcos. Test for your hormonal levels. Reset your adrenals with adaptogen like adhs (vasopressin). Do a lymph clease I use betaine hcl, modified citrus pectin and heavy metal detox (chlorella caps). Pemf resets all these issues.