CHUBBY FACE <3 yeyy =) im 15?

hey im a female , well i just had my GCSE exams for a month so i was under alot of pressure and studied 6-8 hours a day and lost alot of weight, how can i gain the weight back on my face? my face looks like a skeleton :( i look ugly and even my mum told me that, btw its true :( and how can imake my skin lighter and remove eye bags i just want to look bright i have kinda dark hazel nut skin darker than beyonce ;)