Gaining back fat in my face

Hi everyone, I've only recently found this sub and my biggest insecurity is that ive lost any and all fat in my face.

About three years ago, I developed an allergy to wheat and dairy, but I didn't know I was allergic to those specific things until my doctor finally gave me an allergy panel this year. I had been eating wheat and dairy regularly which caused a leaky gut, which means I wasn't retaining any of the nutrients I was eating and septic fluid was leaking through my intestines into my bloodstream. This caused me to drop from a healthy, fit 155 lb weightlifting body down to just above 100lbs. I had a lot of trouble with doctors being willing to explore why I had lost so much weight, because "I looked so good." Her words. One of the most frustrating experiences of my life so far.

I'm only 23 but my cheeks are sunken in so I have mouth lines, and when I smile these extreme wrinkles come out of nowhere on my cheeks and under my eyes. It's so embarrassing and it makes me never want to go back to a no-mask-wearing world. I just feel so disgusting. I know gaining weight overall will help, but I'm having an extremely hard time putting fat on. Has anyone else had this problem, and what foods did you eat to try and help? I've been trying to eat at least half an avocado every day, adding nuts and seeds to salads and eating fattier proteins, but it still seems like my efforts are futile.

Any advice, help or motivation is incredibly welcome.