How can i keep a full face when im loosing weight?

You can't: When you are losing weight, your face will be thinner. When you stop and reach a new weight level, it may fill out. The face gets fatter or thinner along with the rest of the body.

Well,..: It is tough to keep one body part (the face) "full," while you are trying to diet and lose weight elsewhere. A balanced diet with exercise and monitored weight loss will hopefully help your whole body change slowly to accommodate for your weight loss and appearance, so that the "fullness" of your face matches the appearance of the weight you are losing in your body."Slow and steady wins the race."