Some of it should come back as you get better. The reason this is happening is what is known as demineralization, or loss of minerals from the body. The body needs tons of resources to fight this off and if it does not obtain them, then the body uses its reserves (primarily found in teeth, hair, nails, bones, etc). I would supplement yourself with a variety of trace minerals if you want to give your body proper nutrients it needs to fight this off and I would examine calcium, magnesium, iodine, zinc, and selenium.
My hair has grown back in spurts where suddenly I will get a lot of growth for 1-2 weeks and then it subsides for a few months and then grows again. I don’t know what causes this but I suspect it has to do with nutrition levels, acidity (pH), digestion, and general health.
If you have ringworm this makes your hair loss worse. This can come in a variety of forms but typically creates “scab like crusts” throughout the scalp, especially along the edges of your hair line (behind ears, neck, front, etc). This is directly related to candida but is also related to parasites. If you have ringworm I have a bunch of tips for you but it should generally improve as you get better. I’ve had ringworm for the last 10 years and I didn’t know it because it completely covered my scalp in a thick layer. I no longer have it as bad, it just flares up every now and then.