Hello, For underweight add healthy calories: Without radically changing your diet, you can increase your calorie intake with each meal by adding nut or seed toppings, cheese, and healthy side dishes. Try almonds, sunflower seeds, fruit or whole-grain wheat toast. Go nutrient-dense: Instead of eating a lot of empty calories and junk food, focus on eating foods that are rich in nutrients. Consider high-protein meats, which can help you to build muscle. Also, choose nutritious carbohydrates, such as brown rice and other whole grains. It helps ensure your body is receiving as much nourishment as possible, even if you’re dealing with a reduced appetite. Eat mini-meals: If you’re struggling with a curbed appetite due to medical or emotional issues, taking in large portions of food may not seem appealing. Consider eating smaller meals throughout the day to increase your calorie intake. Bulk up: While too much aerobic exercise will burn calories and ultimately work against your weight goal, strength training– such as weight-lifting or yoga–can help you gain weight by building muscle. For sunken eyes: I am sure many doctors will suggest fat injection or filler injection correct your hollow eyes. I strongly urge you not to have injections done into your upper eyelid. There are many very delicate structures in the upper eyelid that can be injured by a needle used for injection, and injury to the levator muscle could give you a droopy eyelid. The safest and most effective method to plump a hollow upper eyelid, in my opinion, is an open composite fat graft. During this procedure, I harvest a small amount of fat from around your belly button , make a small laser incision in the upper eyelid, and graft the fat directly into the hollow area of your upper eyelid. This procedure works very well, has been done for many years, and will give you the best result. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Gaurav Prajapati