This has to be so disruptive to your quality of life. I know it’s difficult to make these adjustments in diet. I’ve had to do that too, for other health related issues. But we are capable of making things work when we have to.

The diet your dermatologist suggested is to help curb the inflammation in your body. Some studies suggest that antioxidants, like vitamin C, vitamin E, beta-carotene, and selenium, may make a difference along with fatty acids from fish oil. My doctors recommended a Mediterranean style diet.

Anti-inflammatory foods are generally healthy, so it won’t hurt to give them a try. Slowly you can add more acceptable foods as you eliminate items that can cause inflammation.

Below is a list of acceptable and healthy foods so you can see that you’re not severely limited in what you eat.
Fruits and veggies, especially berries, cherries, and leafy greens, lentils, dried beans, whole grains, Salmon, sardines, and other fish rich in omega-3 fatty acids.
Antioxidant-rich herbs and spices like thyme, sage, cumin, turmeric and ginger. Green tea is another healthy antioxidant to drink.
Heart-healthy sources of fat, like olive oil, seeds, ground flax seed, nuts.
You might be able to substitute brown rice or wild rice instead of white rice.
If you miss bread, you might consider trying a 12 grain or other whole grain bread in moderation. But avoid white bread.

Foods to avoid which can cause inflammation are:
Processed foods and refined sugars.
Fatty cuts of red meat
Dairy

A little more reading material for you. But these articles are excellent for helping to see why it’s important to eat healthy, what causes inflammation and why it happens.
https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/how-to-use-food-to-help-your-body-fight-inflammation/art-20457586
https://health.clevelandclinic.org/5-foods-that-can-cause-inflammation/
Does this help you feel a little less helpless about changing your diet?