palatal expansion in adults is very limited without an actual expander because the mid-palatal suture is mostly fused after puberty… only orthodontic or surgical expansion changes bone structure.
for fat loss: u can’t spot reduce fat. fat distribution is largely genetic and hormonally regulated. the only reliable way to get leaner overall is a calorie deficit, adequate protein (to preserve muscle), resistance training, and good sleep. as u get skinner, facial fat may decrease too. if ur already lean but but the face still looks puffy probably u just have to debloat
also keep in mind that very low body fat doesn’t always improve facial aesthetics