you probably can't tell from my pictures because I'm smiling, but my face is really gaunt, even at this age. It sometime happens to older people, but with me its an issue already. Any makeup advise, and how to cover a skinny face using makeup ?
You usually see people wanting to get a skinnier face, not the opposite. An even, good foundation that is a shade darker will help you, or a tan. A good foundation will blend in with your jawline and give you a tanned glow/fuller looking face. When applying eyeshadow, blend it outwards and upwards towards your eyebrows. This will create your eyes to look wider and open them up more. When doing your eyebrows, make sure they aren't too thin. You want them shaped and full. Thin ones won't help to make your face look fuller. I suggest that when you use eyeliner on your top lids, flip them out some on the sides to add definition. Use mascara on your outer edges especially. Use blush on the apples of your cheeks (smiling will help you apply). A darker blush with make your face look more fuller but you don't want to go overboard with the colors, you still want it to look natural and not like a clown. Also, a full hairstyle will make your face look fuller as well.
Well besides for makeup I would say some type of fringe/bangs would widen a face that is too thin, especially with a big forehead. In your pictures you look just fine to me! But anyhow I would probably try to gain a few pounds, not too many, I know when I gain like 5 pounds it shows in my face and I have full cheeks to begin with so yeah. But I guess some people have more of a tendency to carry weight in the face than others.
Highlight your cheekbones. Also highlight your eyes nicely so they stand out and pop more. I am not sure how to contour with blush and bronzer but I am sure there is a way to emphasize your cheeks and make them look fuller.