A well-balanced diet is essential for keeping skin healthy, and it helps the wound healing process.
In particular, that diet should include vitamins A, B, C and E, iron and zinc, proteins and carbohydrates.
Some things work against healing. Major weight loss or weight gain, and not getting enough protein, fluids, energy and vitamins, all affect how a wound heals. Body weight itself can affect how a wound heals.
Nutrition is one factor among several, not the whole explanation. Poor nutrition sits alongside diabetes, poor circulation, nerve damage, bone infection, not being able to move around, a weak immune system, heavy alcohol use and smoking as factors that may interfere with wound healing.
Two of those deserve a closer look. Smoking reduces the amount of oxygen reaching the wound, and any scar tissue laid down when the wound heals will be of poorer quality. Alcohol should always be used in moderation, because drinking too much will delay wound healing.
This page is not a diet plan. It names nutrients, not foods, and gives no amounts and no eating plan. For guidance on your own situation, ask a health care professional. That is where a question about what to eat belongs.